Daily AncestorCorrection line
A correction line, or standard parallel, is an east-west survey line run every 24 or 30 miles to correct for the narrowing of townships caused by the earth's curve.
In the federal rectangular survey, range lines run north and drift closer together as they go, because meridians converge. To keep townships near six miles square, surveyors ran standard parallels at set intervals, usually 24 miles north and south of the base line, and restarted the measurements there.
The interval was commonly 24 or 30 miles, depending on the year and place. The 24-mile spacing was set as the rule in the 1881 survey manual.
How to cite this page
Daily Ancestor. "Correction line." Dictionary of Old Record Words. https://dailyancestor.com/dictionary/legal-land/correction-line. Last checked 2026-10-12.