What was known as Louisiana Territory stretched from the Mississippi River in the east to the Rocky Mountains in the west and from the Gulf of Mexico in the south to the Canadian border in the north.
For slaves they could use the Mississppi river for travel
His son, Stephen F. Austin, had the grant confirmed by Mexican authorities after his father’s death, and by the mid-1830s there were about 30,000 Americans ranching and growing cotton with the aid of several thousand black slaves
•The U.S. wanted to take Florida from Spain because of attacks by Seminole Indians and runaway slaves in Georgia.In 1819, President Monroe sent Andrew Jackson to Florida to help protect the U.S. border. Jackson invaded Florida
Frederick Douglas published accounts of successful black miner's in his paper the North Star. This encouraged many to go to California. Most going to the California gold rush were free men but some were brought as slaves to work for their masters. Many earned their freedom and paid for the freedom of their families.
The Willamette Valley was an area of fertile farmland in the Oregon Territory which attracted large numbers of farmers in the 1830s and 1840s, especially those from the Mississippi River Valley. Reports of the abundance of this land sparked the movement of many pioneers to the West Coast.
The Mexican regime was urgently in need of money and for $10 million sold the required strip of territory south of the Gila River, in what is now southern New Mexico and Arizona