The Indiana General Assembly passed a law designating a new state capital where today sits downtown Indianapolis on January 6, 1821, now celebrated as Founders Day. Most of the legislation includes technical instructions about exactly which township sections the new city should be laid out upon and the timeline on which work should be completed. But the legislation does include this stirring vision of what the new capital city should be: “advantageous to the state and to the prosperity of said town having especially in view the health, utility, and beauty of the place.”

The General Assembly hired Andrew Ralston, a Scottish immigrant and surveyor who had previously assisted Pierre L’Enfant on the master plan for Washington, D.C., before relocating to the Ohio River Valley. The Ralston Plan (today the Mile Square) includes many familiar elements: a center circle, four diagonal streets, a statehouse on the west side of town, a county courthouse on the east. He envisioned two markets and six parks placed neatly along the diagonal streets. The neat 10 x 10 grid breaks for Pogue’s Run in the southeast quadrant; the White River demarcates a western boundary.

A colorful rarely seen 1826 map in the collections of the Indiana State Library hews closely to the Ralston Plan but also shows how roads started to link the new capital to the rest of the state. It reveals intriguing quirks such as the not-quite-even alignment of the National Road and Washington Street. Later, of course, street names changed and points on the diagonals were cleared for urban renewal projects; the second market may never have materialized, nor did the six triangle parks Ralston envisioned. Yet 200 years later, Ralston’s plan remains Indianapolis’ blueprint.