Accessory Structures in Harrison County, MS (2026)
2 rules for unincorporated Harrison County, Mississippi.
Verified from official government sources
ADU Rules
A secondary living unit, a garage apartment or in-law suite, is allowed on a single-family lot in unincorporated Harrison County only with a conditional use permit; Section 812 of the Unified Development Code treats it as an accessory structure to the principal detached dwelling, in districts listed in Section 415.
Harrison County Secondary Living Unit Permit
Significant RestrictionsHarrison County Unified Development Code, Art. VIII, § 812 (as amended through Dec. 12, 2022)
A secondary living unit shall be allowed by a conditional use permit as an accessory structure to the principal detached single household dwelling in those zoning districts specified in Section 415.
Shed & Carport Rules
Harrison County caps backyard sheds and other accessory buildings by lot size: on a lot under one acre, Section 815.08 of the Unified Development Code limits an accessory building to 800 square feet (or 50% of the primary home's size, whichever is greater) and 20 feet in height.
Harrison County Accessory Building Size Limits
Some RestrictionsHarrison County Unified Development Code, Art. VIII, § 815.01, 815.04, 815.08, 815.12 (as amended through Dec. 12, 2022)
815.01 The cumulative square footage under roof of all accessory buildings on the property shall not exceed the overall square footage of the primary residential structure. ... 815.04 There shall be no more than two (2) accessory buildings allowed per primary use in R-1, R-2, and R-3 districts and no more than three (3) accessory buildings allowed per primary use in other districts. ... 815.12 ...
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