Bunker Hill Monument by the Numbers: 221 Feet, 294 Steps

The two questions visitors ask most:

• How tall is it? 221 feet 5 inches (67.5 m).
• How many steps? 294.

The Bunker Hill Monument honors those who died at the Battle of Bunker Hill, and it has become a symbol of American unity and a New England landmark. The Bunker Hill Monument Association first envisioned it in 1825 and chose the architect Solomon Willard to lead the work. It was a feat of construction: workers used mostly hand tools, horses hoisted the granite blocks for the first half, and a newly invented steam engine lifted the heavy blocks to finish it. It was North America's largest obelisk until the Washington Monument — more than twice its height — was completed.

Cutaway of the monument's interior. NPS.

Apex and pyramidion

The apex is the monument's top point. Its height means nothing in particular: the association's founders reckoned they could afford an obelisk 220 feet tall, and the mortar between the blocks added another foot or so.

The pyramidion is the four-sided pyramid that traditionally caps an obelisk. Bunker Hill's is plainer than ancient ones, which the Egyptians often covered in reflective gold or silver to honor the power of the sun. Weather wears it hard, so it is restored every couple of decades, most recently in 2023.

Chamber

The chamber, or observation deck, is the room at the top where visitors look out the windows. It is small — around 25 people crowd it — so the Park Service limits how many people can be on the narrow stairway and in the chamber at once. It is 18 ft (5.5 m) high and 11 ft 6 in (3.5 m) across.

Exterior wall

The outer wall is built of granite blocks, each level called a course. Every course had to be made smaller than the one below so the monument tapers skyward. The wall and pyramidion take the most weathering and are repointed about every 25 years. Vents on the north side let in light and air.

Central cone

Inside is a monument within the monument: a central cone over 196 feet tall (196 ft 9 in, or 60 m, to the chamber floor), built of over 800 small granite blocks in 147 courses. It supports the granite spiral stairway, which ties it to the outer wall, and its hollow center ventilates the monument. Each cone block is 1 ft 4 in high and each outer-wall block 2 ft 8 in, and there are two cone courses for every wall course.

Stairway

The circular stairway has 294 steps — again, no special meaning, just the number of 8-inch granite steps needed to reach the chamber — and winds around 8 times. There is no elevator: the technology did not exist when the monument was completed in 1843.

The monument's pyramid-shaped foundation, from Solomon Willard's Plans and Sections of the Obelisk on Bunker's Hill (Charles Cook, lithographer, Boston, 1843).

Foundation

A huge foundation keeps the monument upright. It reaches 12 feet (3.65 m) below ground and is itself pyramid-shaped: 6 courses of granite, 50 feet square at the bottom, narrowing to the 30-foot-square first course above ground. Some of its blocks are 12 feet long. Its 1,400 tons of granite are almost a quarter of the whole monument's weight, about 6,000 tons.

Sources

Rewritten from the National Park Service article "Bunker Hill Monument: By The Numbers" (Boston National Historical Park; public domain), in hubnx's own words. The article gives the 15-foot sides of the pyramidion's base as 4.5 m in one list and 4.6 m in another; only the feet are given here.