District of Columbia, DC Building Setbacks & Zoning: Structure Height Limits (2026)

DC's iconic low skyline is a product of federal law, not local zoning. The Height of Buildings Act of 1910 (codified at 40 USC section 6611-6612) restricts building heights across the District based on street width: a building may not exceed the width of the adjacent street plus 20 feet, subject to absolute caps. On commercial streets the cap is 130 feet, except on a limited stretch of Pennsylvania Avenue NW where 160 feet is allowed. Residential zones cap at 90 feet. The Act also generally prohibits habitable space in roof-level mechanical penthouses and limits the penthouse itself to a height equal to the building's width. DC's own zoning regulations (11 DCMR) layer additional limits: most R-1 zones allow 40 feet and 3 stories, R-4 row house zones allow 40 feet, and commercial MU zones stratify from 50 to 130 feet. Measurement is from the finished grade of the building line to the highest point of the roof (excluding chimneys, antennas, and conforming penthouses). Historic district overlays often impose lower visual heights. The Board of Zoning Adjustment cannot grant variances above the federal Height Act — only Congress can amend it. Efforts to raise the Height Act in 2013 failed in the House despite support from some DC leaders. The result is that even recent Navy Yard and NoMa buildings stop at 130 feet, and the Capitol and Washington Monument remain the visual anchors.