Mount Prospect, IL Building Setbacks & Zoning: Setback Rules (2026)

Section 14.905 B applies to any building or structure constructed or relocated in the R-1 single-family district. For residential uses the table reads: front yard 30 feet, interior side yard 10 percent of lot width or 10 feet whichever is less, exterior side yard 10 feet, rear yard 25 feet. Nonresidential uses in R-1 carry a second table: front 30 feet, interior side 10 feet minimum but not less than half the height of the principal building, exterior side 20 feet, and a rear yard equal to the height of the principal building but not less than 25 feet.

Each district in Chapter 14 prints its own numbers. In R-X, § 14.805 sets a residential front yard of 40 feet, exterior side yard of 25 feet and rear yard of 30 feet. In R-A, § 14.1005 sets a front yard of 30 feet, interior side yard of 5 feet, exterior side yard of 10 feet and rear yard of 25 feet. The R-2 district (§ 14.1105) and R-3 district (§ 14.1205) share a 30 foot front yard, 20 foot exterior side yard and 25 foot rear yard.

Accessory structures follow § 14.306 B.2. On lots fifty five feet wide or less, a detached accessory structure sits three feet from any interior side or rear lot line, and on wider lots five feet. No accessory structure goes on a right of way or Village utility or easement without prior consent from the director of community development.

Relief has two paths. Land Use Table 1 lists Setback reductions in all required yards as a conditional use under R-X, R-1 and R-A, and its note 2 warns that reductions below 5 feet can trigger building code requirements including fire-rated walls, limitation on projections, and opening in walls. Under § 14.203 F.6 the planning and zoning commission decides as final administrative authority a reduction that does not exceed twenty five percent of the requirement and recommends to the Village Board on larger ones. A variation under § 14.203 C requires findings of a specific hardship.