This map of Denver in 1879 was made by H.L. Thayer, a man who was not in the business of selling maps, but instead in the business of selling land – his maps would be used for speculators or bankers. Like the Chicago map, Thayer’s Denver map was printed on light, thin paper, making it perfect to be toted in the pockets of real estate buyers and sellers. Like the Chicago map, Rumsey explains that Thayer’s map of Denver shows a town in full-blown expansion. Denver was founded in 1858 during the Pike’s Peak gold rush; the city was only 21 years old when this map was drawn. The additions highlighted on the map – Stiles Addition, Schiners Addition, and the others – were all expanding neighborhoods named for the men who developed them.

“What is really fun to see, particularly on the old map, using the spyglass, is the river,” Rumsey explains. “You can see how it’s really been channeled.” Indeed, dragging the spyglass over the Platte River, one can see how a once divergent river was channeled into a straight and narrow path by developers hoping to expand buildable land.

Rumsey also points out the contrasting grid system of the city, explaining how the downtown area was built on a 45-degree angled grid, while the outlaying residential areas were built in a north-south grid, known as a township and range grid. “My guess is that these township and range grids probably came later to Denver,” Rumsey explains, noting how the angled downtown area was the first settled part of the city. “These grids are still there today,” Rumsey adds. “These decisions, made by individuals, become part of the fabric of the city.”