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

Table 7-A of the Land Use Code, Article 7 § 7.3, 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.