Correction Line Road

Musing about rectangular vs polar views of the world led to an old memory. Once in the 80s I visited a friend who had moved to the country near Dodge City. He lived on Correction Line Road.

The name has nothing to do with jails. It has everything to do with the Louisiana Purchase and the system of surveying the new lands west of the Mississippi. Surveys divided the land into townships, each 6×6 miles, and then into square miles within the township. A classic 12-based system, following Roman and English tradition of 12-based fractions.

The layout was calibrated by latitudes and longitudes to give the surveyors a universal standard. From any location they could sight a reference star, keep an accurate clock, and find the longitude and latitude from a table plus some calculations.

PROBLEM: Longitudes are a polar graph, gradually getting wider as you go south. The townships and miles needed to be a strict rectangular graph, pretending the earth is flat. Otherwise a square mile in Texas would be much wider than a square mile in North Dakota. The Texas Mile would be literally true.

SOLUTION: At fixed intervals a Correction Line latitude was marked, and the next rectangle to the south started with accurate longitudes again. The surveyors could calibrate by longitudes when they started into each new interval. Between the Correction Lines they would pretend the earth is flat and work in rectangular form.

Later the townships became administrative boundaries, and often got reshaped or merged to fit geographical limits like rivers or mountains.

I got curious to see if the road was still named.

Here’s a larger view of the longitudinal roads above and below the Correction Line.