Earth

Earth was a world on an alternate Material Plane.

People
The Mulan peoples originally came from another world, widely believed to have been Earth. To replenish their population after a devastating plague, the mages of the Imaskar Empire opened two great gates to this other world, and kidnapped numerous humans to serve as their slaves. Those of Mulhorand hailed from a desert land given life by the seasonal flooding of a great river; those of Unther from a land of empire and glory, and those of Chessenta from a collection of city-states known for their daring philosophies. After transporting them back to Abeir-Toril, they closed the gates forever. Intermarrying both with each other and the Imaskari, they became the Mulan. With them, they brought their own societies, mature culture, and later, the gods of the Mulhorandi and Untheric pantheons.

In the Year of the Prince, 1357 DR, an inhabitant of Earth called Ed of the Greenwood assembled various journals, maps, and other works from Elminster Aumar into the first publication of the Forgotten Realms campaign setting.

Laeral Silverhand also regularly traveled to Earth to visit Steven E. Schend and spoke to him of Waterdeep, even if she did tend to interrupt his writing. He compiled the lore into articles for Dragon magazine.

Fauna
Foxes were never native to Toril, and were actually brought from France by an adventurous halfling trader named Altho Minstrelwish

Locations
The Pecos River was a river on Earth. St. Sollars the Twice-Martyred described the demon lord Orcus, Prince of the Undead, as "the meanest dude this side o' the Pecos".