Designed by Jonathan Doane, the original structure has seen architectural inputs from other notable architects across the centuries.

It offers daily tours to the public and provides an educational platform for middle and high school students.

In 1845, Philadelphia architect John Notman created a three-stepped office wing on the north side of the original building.

[2] In 1903, Merchantville architect Arnold Moses reconstructed the Senate wing in the American Renaissance style.

The project encompassed the legislative section of the building, an upgrade of mechanical and electrical systems, and the construction of the South Addition (office space).

[2] In 2017, a $300M restoration of the entire building mainly focused on the governor's office and related Executive Branch agencies began[4][5] and was scheduled to finish in 2023.

A long portico wing, added by Notman and subsequently enlarged, extends west from the rotunda toward the Delaware River.

Viewed from State Street, the dome is scarcely visible and there is little sense of the scale or design of the building.

The tours typically include the Senate and Assembly chamber galleries, the rotunda, and governor's office reception room.