The Michigan State Capitol is 267 feet from the ground to the tip of finial/spire above the dome. The building is 420 feet and two inches long and 273 feet and 11 inches wide (including approaches). The capitol occupies 1 and 1/6 acres, has a perimeter of 1,520 feet. There are four stories in the building, with public entrances on the ground floor. Two grand staircases in the north and south corridors go up to the top floor. The rotunda measures 44.5 feet in diameter and 160 feet in height measured from the floor to the oculus.
The ground floor corridors led to "store rooms" designed by the architect in the original building plans. This includes an armory in the southwest corner of the south corridor. The original wood floor has been replaced by gray tiles. The rooms were originally lit with gas fixtures, though by 1900, the entire building had been refitted with electric lights.
Starting with the first floor and continuing to the third, black and white floor tiling is made of Vermont marble and limestone. The exception is the floor of the rotunda which is composed of 976 blocks of translucent glass. The blocks vary in size so that when viewed from the upper floors, they appear to form a bowl which mirrors the dome above. The doorknobs are mostly made of a brass and bronze alloy (most of the original brass doorknobs have disappeared over time). The present doorknobs and hinges, locked for protection, display the state coat of arms. Though the building appears to have walnut woodwork, the wood is actually Michigan white pine that has been wood-grained to give the appearance of walnut.
The Capitol Pediment, located above the main front entrance to the building, is entitled "The Rise and Progress of Michigan." It depicts a central figure, Michigan, who is dressed as a Native American. She offers a book and globe to the people of her state, promising a bright future. She is surrounded by symbols of Michigan's economy, including a plow, cornucopia, and a laurel wreath to represent agriculture. Also included are symbols representing shipping, mining, and lumbering.
The cornerstone, located at the northeast corner of the building, is a large stone with dates carved on it. On one side is "1872", which marks the start of construction of the capitol. On the other side is "1878", marking the year of completion. The stone was opened during ceremonies on November 15, 1978, the centennial of the building's completion. Various documents enclosed within the stone had been damaged by weather, although several coins from the era were recovered.