The first or Prime Meridian of the Dominion Land Survey was established at 97 degrees 27' 28.4" west longitude. It passes just west of Winnipeg. The location of the First Meridian was chosen because it marked the western limit of settlement.

The meridians were determined by painstaking survey observations and measurements, and in reference to other benchmarks on the continent, but were determined using 19th century technology. The only truly accurate benchmarks at that time were near the prime meridian in Europe. Benchmarks in other parts of the world had to be estimated by the positions of the sun and stars. Although the meridians were remarkably accurate for the time, today they are known to be several hundred metres in error.

Did You Know?

- All Saskatchewan land lies between the first and fourth meridians?
- Saskatchewan's western boundary, the fourth meridian, forms the world's longest surveyed straight line?
- Saskatchewan's eastern boundary is not a straight line but rather has a stepped appearance?