Ridgely

Caroline County, MD (population ~33,000; rural Eastern Shore agricultural county whose seat is Denton) regulates accessory dwelling units under Chapter 175 (Zoning), Article IX (Accessory Structures and Uses), Section 175-83. The county code defines an ADU as separate living quarters - with its own kitchen, living, and sleeping areas - located within the principal dwelling or in a detached accessory structure. Owner-occupancy of either the principal or accessory unit is required, and the principal and accessory unit must be in common ownership and cannot be subdivided from each other. The ADU must be located in a side or rear yard, no closer to the front lot line than the principal dwelling, and no more than 100 feet from the principal dwelling if detached. Total habitable area must be at least 400 square feet and not exceed 1,000 square feet, and the ADU cannot be larger than 50% of the principal dwelling. One ADU is permitted per lot. Mobile homes are not permitted as ADUs under Section 175-83 (the county's separate Article VIII governs mobile homes). The 2025 statewide ADU framework (Maryland HB 1466 / SB 891, signed by Governor Wes Moore on 2025-04-21, effective 2025-10-01) requires local-jurisdiction compliance by 2026-10-01; Caroline County's existing Section 175-83 was on the books before HB 1466 and must be conformed to the state floor by that deadline. As of the verification date the county had not yet adopted a HB 1466 conforming amendment.

• Caroline County Code, Chapter 175 (Zoning), Article IX (Accessory Structures and Uses), Section 175-83 (Accessory Dwelling Units)
• Maryland HB 1466 / SB 891 (2025) - Accessory Dwelling Units Act of 2025

State-floor overlay: Maryland HB 1466 (2025) establishes a statewide ADU floor that local jurisdictions must conform to by 2026-10-01. Caroline County's pre-existing Section 175-83 is generally permissive but has not yet been amended to align with the HB 1466 framework; the state floor will control to the extent of any conflict.

Caroline County administers three overlay regimes that materially affect ADU project feasibility: (1) the Chesapeake Bay Critical Area, which applies to all land within 1,000 feet of the Choptank River, the Tuckahoe Creek, the Marshyhope Creek, and their tidal tributaries; (2) FEMA NFIP floodplain rules, with floodplain overlay districts established as overlays on the Official Zoning District Maps; and (3) Forest Conservation Act review for projects that disturb 40,000 square feet or more. The Critical Area regime is the most distinctive Caroline County overlay: substantial portions of the southern and western parts of the county (and a corridor along the Choptank through Denton, Greensboro, and Federalsburg) fall inside the 1,000-foot Critical Area envelope, and the Maryland Critical Area Commission's IDA / LDA / RCA classification of a parcel controls density, impervious-coverage caps, and buffer rules for any new structure including an ADU.

• Chesapeake Bay Critical Area (Caroline County) — Contact Matt Kaczynski at the Caroline County Planning and Codes Department (410-479-8100) for Critical Area determinations.
• FEMA NFIP Special Flood Hazard Areas in Caroline County — A new ADU in a mapped SFHA must be elevated to or above the Base Flood Elevation; cost impact on the project is often material on this low-lying Eastern Shore county.
• Forest Conservation Act review (Caroline County) — Most single-ADU additions on existing residential lots stay below the FCA trigger; verify at intake for larger parcels.

The Caroline County Department of Planning and Codes (established 1985) administers zoning and building-permit review for unincorporated Caroline County from offices at 403 South 7th Street, Suite 210, Denton, MD 21629. The department operates a unified planning, zoning, and codes-administration function; it also handles erosion and sediment control, forest conservation, stormwater management, Critical Areas, floodplain management, and addressing. Applications are submitted through the county's online portal at https://caroline.onlama.com/. Inside the eight incorporated municipalities (Denton, Federalsburg, Goldsboro, Greensboro, Henderson, Hillsboro, Preston, Ridgely) the town issues its own building and zoning permits; the county's authority covers only unincorporated territory plus any town that has contracted county services.