diff --git a/changelog.d/id-ssp.added.md b/changelog.d/id-ssp.added.md
new file mode 100644
index 00000000000..bd7cd3c0e6d
--- /dev/null
+++ b/changelog.d/id-ssp.added.md
@@ -0,0 +1 @@
+Added Idaho Aid to the Aged, Blind, and Disabled (AABD) cash assistance program.
diff --git a/policyengine_us/parameters/gov/household/household_state_benefits.yaml b/policyengine_us/parameters/gov/household/household_state_benefits.yaml
index 9573ff8c17e..6814e3880bf 100644
--- a/policyengine_us/parameters/gov/household/household_state_benefits.yaml
+++ b/policyengine_us/parameters/gov/household/household_state_benefits.yaml
@@ -26,6 +26,8 @@ values:
     - al_ssp
     # Alaska benefits
     - ak_ssp
+    # Idaho benefits
+    - id_aabd
     # Nebraska benefits
     - ne_child_care_subsidies
     # Massachusetts benefits
@@ -57,6 +59,8 @@ values:
     - al_ssp
     # Alaska benefits
     - ak_ssp
+    # Idaho benefits
+    - id_aabd
     # Nebraska benefits
     - ne_child_care_subsidies
     # North Carolina benefits
diff --git a/policyengine_us/parameters/gov/states/id/dhw/aabd/payment/amount.yaml b/policyengine_us/parameters/gov/states/id/dhw/aabd/payment/amount.yaml
new file mode 100644
index 00000000000..46ac8e94f92
--- /dev/null
+++ b/policyengine_us/parameters/gov/states/id/dhw/aabd/payment/amount.yaml
@@ -0,0 +1,31 @@
+description: >-
+  Idaho provides this maximum monthly AABD cash payment amount based on
+  the participant's living arrangement.
+metadata:
+  unit: currency-USD
+  period: month
+  label: Idaho AABD maximum monthly cash payment
+  breakdown:
+  - id_aabd_living_arrangement
+  reference:
+    - title: IDAPA 16.03.05.514 - AABD Cash Payments
+      href: https://adminrules.idaho.gov/rules/current/16/160305.pdf#page=41
+    - title: IDAPA 16.03.05.514 - AABD Cash Payments (2022 Archive)
+      href: https://adminrules.idaho.gov/rules/2022%20Archive/16/160305.pdf#page=55
+    - title: Idaho Admin. Code r. 16.03.05.514
+      href: https://www.law.cornell.edu/regulations/idaho/IDAPA-16.03.05.514
+
+SINGLE:
+  2022-07-01: 53
+COUPLE:
+  2022-07-01: 20
+ESSENTIAL_PERSON:
+  2022-07-01: 18
+SIGRIF:
+  2022-07-01: 169
+ROOM_AND_BOARD:
+  2022-07-01: 198
+RALF_CFH:
+  2022-07-01: 0
+NONE:
+  2022-07-01: 0
diff --git a/policyengine_us/parameters/gov/states/id/dhw/aabd/payment/basic_allowance.yaml b/policyengine_us/parameters/gov/states/id/dhw/aabd/payment/basic_allowance.yaml
new file mode 100644
index 00000000000..83ba8660df7
--- /dev/null
+++ b/policyengine_us/parameters/gov/states/id/dhw/aabd/payment/basic_allowance.yaml
@@ -0,0 +1,32 @@
+description: >-
+  Idaho sets this amount as the monthly basic living allowance for AABD
+  participants based on living arrangement under the Aid to the Aged,
+  Blind, and Disabled program.
+metadata:
+  unit: currency-USD
+  period: month
+  label: Idaho AABD basic living allowance
+  breakdown:
+  - id_aabd_living_arrangement
+  reference:
+    - title: IDAPA 16.03.05.501 - Basic Living Allowance
+      href: https://adminrules.idaho.gov/rules/current/16/160305.pdf#page=39
+    - title: IDAPA 16.03.05.501 - Basic Living Allowance (2022 Archive)
+      href: https://adminrules.idaho.gov/rules/2022%20Archive/16/160305.pdf#page=53
+    - title: IDAPA 16.03.05.512 - Room and Board Allowance
+      href: https://adminrules.idaho.gov/rules/current/16/160305.pdf#page=40
+
+SINGLE:
+  2022-07-01: 545
+COUPLE:
+  2022-07-01: 768
+ESSENTIAL_PERSON:
+  2022-07-01: 768
+SIGRIF:
+  2022-07-01: 349
+ROOM_AND_BOARD:
+  2022-07-01: 770
+RALF_CFH:
+  2022-07-01: 96
+NONE:
+  2022-07-01: 0
diff --git a/policyengine_us/tests/policy/baseline/gov/states/id/dhw/aabd/id_aabd.yaml b/policyengine_us/tests/policy/baseline/gov/states/id/dhw/aabd/id_aabd.yaml
new file mode 100644
index 00000000000..8bf652af1ce
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/gov/states/id/dhw/aabd/id_aabd.yaml
@@ -0,0 +1,108 @@
+- name: Case 1, RALF/CFH resident ineligible for AABD cash.
+  period: 2025-01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 4_800
+        id_aabd_living_arrangement: RALF_CFH
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    id_aabd_eligible: [false]
+    id_aabd: [0]
+
+- name: Case 2, NONE arrangement ineligible.
+  period: 2025-01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 4_800
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    id_aabd_eligible: [false]
+    id_aabd: [0]
+
+- name: Case 3, no SSI ineligible.
+  period: 2025-01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 12_000
+        id_aabd_living_arrangement: SINGLE
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    id_aabd_eligible: [false]
+    id_aabd: [0]
+
+- name: Case 4, non-Idaho resident.
+  period: 2025-01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 4_800
+        id_aabd_living_arrangement: SINGLE
+    households:
+      household:
+        members: [person1]
+        state_code: CA
+  output:
+    id_aabd: [0]
+
+- name: Case 5, nursing facility resident excluded from AABD.
+  period: 2025-01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 1_200
+        ssi_lives_in_medical_treatment_facility: true
+        ssi_medicaid_pays_majority_of_care: true
+        id_aabd_living_arrangement: SINGLE
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    # Federal LA = MEDICAL_TREATMENT_FACILITY, excluded by eligibility
+    id_aabd_eligible: [false]
+    id_aabd: [0]
+
+- name: Case 6, eligible person with ineligible spouse uses SINGLE not COUPLE.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 4_800
+        id_aabd_living_arrangement: SINGLE
+      person2:
+        age: 30
+    marital_units:
+      marital_unit:
+        members: [person1, person2]
+        marital_unit_id: 0
+    spm_units:
+      spm_unit:
+        members: [person1, person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_code: ID
+  output:
+    # Per 501.01: "living with their ineligible spouse" = SINGLE
+    # Per 501.02: COUPLE requires both to be AABD participants
+    # Person1 gets individual rate ($53), not couple rate ($10)
+    id_aabd: [53, 0]
diff --git a/policyengine_us/tests/policy/baseline/gov/states/id/dhw/aabd/integration.yaml b/policyengine_us/tests/policy/baseline/gov/states/id/dhw/aabd/integration.yaml
new file mode 100644
index 00000000000..53f0acf714f
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/gov/states/id/dhw/aabd/integration.yaml
@@ -0,0 +1,195 @@
+- name: Case 1, single with low income gets max AABD.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 4_800
+        id_aabd_living_arrangement: SINGLE
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    # Countable: ($4,800 - $240 disregard) / 12 = $380/mo
+    ssi_countable_income: [380]
+    # SSI: ($11,604 - $4,560) / 12 = $587/mo
+    ssi: [587]
+    id_aabd_eligible: [true]
+    # Need: $545 - $380 = $165; min($165, $53) = $53
+    id_aabd: [53]
+
+- name: Case 2, single with moderate income gets reduced AABD.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 6_240
+        id_aabd_living_arrangement: SINGLE
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    # Countable: ($6,240 - $240) / 12 = $500/mo
+    ssi_countable_income: [500]
+    # SSI: ($11,604 - $6,000) / 12 = $467/mo
+    ssi: [467]
+    id_aabd_eligible: [true]
+    # Need: $545 - $500 = $45; min($45, $53) = $45
+    id_aabd: [45]
+
+- name: Case 3, single with high income receives SSI but no AABD need.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 7_200
+        id_aabd_living_arrangement: SINGLE
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    # Countable: ($7,200 - $240) / 12 = $580/mo
+    ssi_countable_income: [580]
+    # SSI: ($11,604 - $6,960) / 12 = $387/mo
+    ssi: [387]
+    id_aabd_eligible: [true]
+    # Need: max(0, $545 - $580) = $0
+    id_aabd: [0]
+
+- name: Case 4, couple both SSI recipients.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 2_400
+        id_aabd_living_arrangement: COUPLE
+      person2:
+        age: 70
+        social_security: 2_400
+        id_aabd_living_arrangement: COUPLE
+    marital_units:
+      marital_unit:
+        members: [person1, person2]
+        marital_unit_id: 0
+    spm_units:
+      spm_unit:
+        members: [person1, person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_code: ID
+  output:
+    # Combined SS: $4,800/yr, disregard $240 once
+    # Combined countable: $4,560/yr, per person: $2,280/yr = $190/mo
+    ssi_countable_income: [190, 190]
+    # Couple FBR: $17,400/yr, SSI: $12,840/yr, per person: $535/mo
+    ssi: [535, 535]
+    id_aabd_eligible: [true, true]
+    # Per-person allowance: $768/2 = $384
+    # Need: $384 - $190 = $194; max per person: $20/2 = $10
+    # AABD: min($194, $10) = $10
+    id_aabd: [10, 10]
+
+- name: Case 5, SIGRIF resident with low income.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 2_400
+        id_aabd_living_arrangement: SIGRIF
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    # Countable: ($2,400 - $240) / 12 = $180/mo
+    ssi_countable_income: [180]
+    # SSI: ($11,604 - $2,160) / 12 = $787/mo
+    ssi: [787]
+    id_aabd_eligible: [true]
+    # Need: $349 - $180 = $169; min($169, $169) = $169
+    id_aabd: [169]
+
+- name: Case 6, room and board resident with low income.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 4_800
+        id_aabd_living_arrangement: ROOM_AND_BOARD
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    # Countable: $380/mo
+    ssi_countable_income: [380]
+    # SSI: $587/mo
+    ssi: [587]
+    id_aabd_eligible: [true]
+    # Need: $770 - $380 = $390; min($390, $198) = $198
+    id_aabd: [198]
+
+- name: Case 7, essential person arrangement with low income.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 4_800
+        id_aabd_living_arrangement: ESSENTIAL_PERSON
+    households:
+      household:
+        members: [person1]
+        state_code: ID
+  output:
+    # Countable: $380/mo (individual, not couple)
+    ssi_countable_income: [380]
+    # SSI: $587/mo
+    ssi: [587]
+    id_aabd_eligible: [true]
+    # Need: $768 - $380 = $388; min($388, $18) = $18
+    id_aabd: [18]
+
+- name: Case 8, asymmetric couple, one not ABD gets individual rate.
+  period: 2025-01
+  absolute_error_margin: 0.01
+  input:
+    people:
+      person1:
+        age: 70
+        social_security: 4_800
+        id_aabd_living_arrangement: SINGLE
+      person2:
+        age: 30
+    marital_units:
+      marital_unit:
+        members: [person1, person2]
+        marital_unit_id: 0
+    spm_units:
+      spm_unit:
+        members: [person1, person2]
+    households:
+      household:
+        members: [person1, person2]
+        state_code: ID
+  output:
+    id_aabd_eligible: [true, false]
+    # Person1: individual, countable $380/mo
+    # Need: $545 - $380 = $165; min($165, $53) = $53
+    id_aabd: [53, 0]
diff --git a/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd.py b/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd.py
new file mode 100644
index 00000000000..822990e39b4
--- /dev/null
+++ b/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd.py
@@ -0,0 +1,37 @@
+from policyengine_us.model_api import *
+from policyengine_us.variables.gov.states.id.dhw.aabd.id_aabd_living_arrangement import (
+    IDAAbdLivingArrangement,
+)
+
+
+class id_aabd(Variable):
+    value_type = float
+    entity = Person
+    label = "Idaho AABD cash payment"
+    unit = USD
+    definition_period = MONTH
+    defined_for = "id_aabd_eligible"
+    reference = (
+        "https://adminrules.idaho.gov/rules/current/16/160305.pdf#page=41",
+        "https://www.law.cornell.edu/regulations/idaho/IDAPA-16.03.05.514",
+    )
+
+    def formula(person, period, parameters):
+        la = person("id_aabd_living_arrangement", period)
+        p = parameters(period).gov.states.id.dhw.aabd.payment
+        LA = IDAAbdLivingArrangement
+
+        basic_allowance = p.basic_allowance[la]
+        max_payment = p.amount[la]
+
+        # Couples: regulation defines combined amounts (Section 501.02)
+        # Both spouses are AABD participants, each gets half
+        is_couple = la == LA.COUPLE
+        per_person_allowance = where(is_couple, basic_allowance / 2, basic_allowance)
+        per_person_max = where(is_couple, max_payment / 2, max_payment)
+
+        # AABD cash = basic allowance - countable income, capped at max
+        # (Section 514). Idaho mirrors SSI disregards (Sections 540-546).
+        countable_income = person("ssi_countable_income", period)
+        financial_need = max_(0, per_person_allowance - countable_income)
+        return min_(financial_need, per_person_max)
diff --git a/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd_eligible.py b/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd_eligible.py
new file mode 100644
index 00000000000..2457160fe18
--- /dev/null
+++ b/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd_eligible.py
@@ -0,0 +1,27 @@
+from policyengine_us.model_api import *
+from policyengine_us.variables.gov.states.id.dhw.aabd.id_aabd_living_arrangement import (
+    IDAAbdLivingArrangement,
+)
+
+
+class id_aabd_eligible(Variable):
+    value_type = bool
+    entity = Person
+    label = "Idaho AABD eligible"
+    definition_period = MONTH
+    defined_for = StateCode.ID
+    reference = (
+        "https://adminrules.idaho.gov/rules/current/16/160305.pdf#page=41",
+        "https://www.law.cornell.edu/regulations/idaho/IDAPA-16.03.05.514",
+    )
+
+    def formula(person, period, parameters):
+        receives_ssi = person("ssi", period) > 0
+        la = person("id_aabd_living_arrangement", period)
+        LA = IDAAbdLivingArrangement
+        # Nursing facility residents excluded (Section 501)
+        federal_la = person("ssi_federal_living_arrangement", period.this_year)
+        not_in_medical = (
+            federal_la != federal_la.possible_values.MEDICAL_TREATMENT_FACILITY
+        )
+        return receives_ssi & not_in_medical & (la != LA.RALF_CFH) & (la != LA.NONE)
diff --git a/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd_living_arrangement.py b/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd_living_arrangement.py
new file mode 100644
index 00000000000..57c242d0cdc
--- /dev/null
+++ b/policyengine_us/variables/gov/states/id/dhw/aabd/id_aabd_living_arrangement.py
@@ -0,0 +1,25 @@
+from policyengine_us.model_api import *
+
+
+class IDAAbdLivingArrangement(Enum):
+    SINGLE = "Single participant"
+    COUPLE = "Couple"
+    ESSENTIAL_PERSON = "Participant with essential person"
+    SIGRIF = "Semi-independent group residential facility"
+    ROOM_AND_BOARD = "Room and board"
+    RALF_CFH = "Residential assisted living facility or certified family home"
+    NONE = "Not applicable"
+
+
+class id_aabd_living_arrangement(Variable):
+    value_type = Enum
+    entity = Person
+    label = "Idaho AABD living arrangement"
+    definition_period = MONTH
+    defined_for = StateCode.ID
+    possible_values = IDAAbdLivingArrangement
+    default_value = IDAAbdLivingArrangement.NONE
+    reference = (
+        "https://adminrules.idaho.gov/rules/current/16/160305.pdf#page=39",
+        "https://www.law.cornell.edu/regulations/idaho/IDAPA-16.03.05.514",
+    )
diff --git a/policyengine_us/variables/household/income/spm_unit/spm_unit_benefits.py b/policyengine_us/variables/household/income/spm_unit/spm_unit_benefits.py
index 84cb7e78d39..edc8eb29f77 100644
--- a/policyengine_us/variables/household/income/spm_unit/spm_unit_benefits.py
+++ b/policyengine_us/variables/household/income/spm_unit/spm_unit_benefits.py
@@ -15,6 +15,7 @@ def formula(spm_unit, period, parameters):
             "ga_ssp",
             "al_ssp",
             "ak_ssp",
+            "id_aabd",  # Idaho benefits
             "de_ssp",  # Delaware benefits
             "ma_state_supplement",  # Massachusetts benefits
             # California programs.