The following map comes from the David Rumsey Map Collection. We recently asked David Rumsey, a map expert who has been collecting maps since the 1980s, to describe the nature of the map to us. His personal map collection currently contains more than 150,000 maps and is one of the largest private collections in the United States.

This 1859 map of San Francisco was extremely utilitarian. The map is a chart, used primarily by sailors and those looking to navigate their way to the city on the bay.. “How did you get to San Francisco in 1859? You got there by boat, so charts were incredibly important,” Rumsey explains. The US Coast Survey drew the chart, perhaps as one of their earliest projects. “The US Coast Survey was a very young organization in 1859, but they spent a lot of time making charts of San Francisco,” Rumsey says.

As with other maps, this old view of San Francisco shows how much the city expanded; the area of Mission Bay on the map that clearly marks a literal bay is a fully developed neighborhood today. “That’s one of the major land changes that’s shown on the map,” Rumsey says. “You can see vast areas of swamp, all that is built up now.” But expanding into the bay had its unique difficulties, as San Francisco’s location along the San Andreas Fault makes it a prime candidate for devastating earthquakes. Because the soil lacks rock, during an earthquake, something called liquefaction occurs, causing the soil to become completely liquefied. “When you build there you have to put piles down to bedrock, which is about 100-200 feet down,” Rumsey explains, noting that this unique feature made expansion harder – though clearly not impossible – for San Francisco.