The 31st parallel north is a circle of latitude that is 31 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Pacific Ocean, North America, and the Atlantic Ocean. At this latitude the sun is visible for 14 hours, 10 minutes during the summer solstice and 10 hours, 8 minutes during the winter solstice. Part of the border between Iran and Iraq is defined by the parallel. In the United States, it defines part of the border between the states of Mississippi and Louisiana, and most of the border between Alabama and Florida. Andrew Ellicott surveyed this parallel in 1797, which in Pinckney's Treaty two years before had been defined as the border between the United States and the Spanish territory of West Florida.

Around the world

Starting at the Prime Meridian and heading eastwards, the parallel 31° north passes through: ! scope="col" width="125" | Coordinates ! scope="col" | Country, territory or sea ! scope="col" | Notes ! scope="row" | 🇩🇿 ! scope="row" | 🇹🇳 ! scope="row" | 🇱🇾 ! scope="row" style="background:#b0e0e6;" | Mediterranean Sea ! scope="row" | 🇱🇾 ! scope="row" | 🇪🇬 ! scope="row" style="background:#b0e0e6;" | Mediterranean Sea ! scope="row" | 🇪🇬 ! scope="row" | 🇮🇱 ! scope="row" | 🇯🇴 ! scope="row" | 🇸🇦 ! scope="row" | 🇮🇶 ! scope="row" | 🇮🇷 / 🇮🇶 border ! scope="row" | 🇮🇷 ! scope="row" | 🇦🇫 ! scope="row" | 🇵🇰 ! scope="row" | 🇮🇳 ! scope="row" | ! scope="row" style="background:#b0e0e6;" | East China Sea ! scope="row" | 🇯🇵 ! scope="row" style="background:#b0e0e6;" | Pacific Ocean ! scope="row" | 🇲🇽 ! scope="row" style="background:#b0e0e6;" | Gulf of California ! scope="row" | 🇲🇽 ! scope="row" | 🇺🇸 ! scope="row" style="background:#b0e0e6;" | Atlantic Ocean ! scope="row" | 🇲🇦 ! scope="row" | 🇩🇿