1st meridian

1st meridian may refer to:


 * 1st meridian east, a line of longitude east of the Greenwich Meridian
 * 1st meridian west, a line of longitude west of the Greenwich Meridian
 * First principal meridian in Ohio and Indiana, United States, 84°48'50" west of Greenwich
 * Principal meridian of the Dominion Land Survey in Canada, 97°27′28.41″ west of Greenwich
 * Counter Revolutionary Warfare Unit aka First Meridian Squadron, a former special forces unit in the Fijian military