Portland, ME Building Setbacks & Zoning: Structure Height Limits (2026)

3, sets the maximum structure height for each Residential Neighborhood (RN) zone unless the City of Portland Height Map or the Fort Sumner Park Height Overlay governs instead. In the RN-1, RN-2, and RN-3 zones, Portland's single-family and two/three-family neighborhoods, the ceiling is a flat 35 feet. RN-4 carries the same 35-foot base but allows 45 feet for buildings with three or more dwelling units; even then, any portion of the building within 15 feet of a rear lot line abutting an RN-1, RN-2, or RN-3 zone is capped back down to 35 feet, a step-back rule meant to protect adjoining lower-density lots from a wall of taller construction at the property line.

RN-5 tops out at 18 feet. RN-6, the densest RN zone, allows 65 feet citywide, but drops to 45 feet within 15 feet of any RN-1, RN-2, RN-3, RN-4, OS-R, or OS-P zone, again buffering lower-density and open-space neighbors. Height is measured under the Article 7 rules of measurement, and a story exceeding 18 feet counts as two stories for that purpose. A property owner planning new construction or a vertical addition needs a building permit before work begins, and the Planning and Urban Development Department checks proposed height against these Table 7-A limits, and the citywide Height Map where it applies, as part of that review.