What is a baseline in a survey grid?
A baseline is the east–west reference line that, together with a principal meridian, anchors a township-and-range survey. Township numbers count north or south of it.
Baselines and meridians
Every principal meridian has an initial point where it crosses a baseline. Townships are numbered north/south from the baseline and ranges east/west from the meridian.
Last reviewed June 2026. General information about survey systems — not legal, title, or survey advice.
Sources: US BLM — Cadastral Survey (PLSS), Natural Resources Canada — About Canada Lands surveys.