In 1817 the United States government signed the Fort Meigs or Maumee Rapids Treaty with several Native American tribes in northern Ohio, including the Seneca Indians, and the Seneca ceded all claims to land north of the Greenville Treaty line in return for a 40,000 acre reservation at Lower Sandusky (Fremont) and a $500 annuity to be paid each year in perpetuity. The reservation began 1.5 miles north of Green Springs, extended 6.5 miles south, was 8 miles wide, and had its western boundary at the Sandusky River. Beginning in 1830, under the Indian removal policy developed by the administration of Andrew Jackson, tribes east of the Mississippi River were pressured to move to reservations in the West, and the Seneca Indians moved to northeast Oklahoma in 1831. Green Springs was also known for Mineral Springs, said to be one of the largest mineral springs in the world, flowing from an underground river at a rate of 8 million gallons every 24 hours, with overflow running into Green Creek and eventually Sandusky Bay and Lake Erie. In the early 1800s Jacob Stem, the founder of Green Spring, used the water to establish the area's first saw and grist mills, but the spring, which remains at a constant 50 degrees year round, became known as a source for curing ailments. In 1868 local entrepreneur Robert Smith had the emerald green water analyzed and found it high in calcium sulphate and magnesium sulphate, after which the area was developed with hotels and spas, drew visitors from many parts of Ohio and elsewhere, and its water was bottled and sold until the 1930s.