Completar frases Green Line 4 p 60 From sea to shining seaVersión en línea Fill the gaps por Natalia Tolstopyat 1 territory frontier front homeland taught fought In the 18th and the 19th century the US grew considerably . The moved further and further west until it finaly reached the Pacific Ocean . By 1773 there had been 12 British colonies on the eastern coast of the North American Continent . After a series of conflicts the American Revolutionary War started between the colonists and their mother country in 1775 . The French helped the Americans to break away from Britain , and even the Spanish and some Native Tribes on their side . When the war ended in 1783 , the British colonies became independent as the United States of America , and Britain gave up the land east of the Mississippi River , north of Florida and south of Quebec ( which later became part of Canada ) . In 1803 the US signed a treaty to buy a large piece of land west of the Mississippi from the French and in this way doubled its size . 2 Purchase fought of fought treaty especially Buying purchase the over a This was called the Louisiana . In 1818 another with Britain secured a part of what now belongs to Minnesota , North and South Dakota for the US . One year later the Spanish decided to give up Florida to the US . In the first part of the 19th century British and Americans had the land in the Northwest , but in 1846 it became part of the US as Oregon Country . In the South and the Southwest the Americans fought over the land with Mexico . The US took control of Texas in 1845 and at the end of the Mexican - American War in 1848 won large parts of today's southwestern states from the Mexicans . One of these regions was California which became attractive because people found gold there in the same year . Finally the US bought another part of Mexico in 1853 . The completed the lower 48 . Alaska and Hawaii became parts of US later . 3 patriots pioneers materials conquer resources cars wagons From 1862 the Homestead Acts allowed settlers to buy land west of the Mississippi , so large number of started to the open country in the West . There are lots of stories and films about how they travelled across the great Plains in covered and how they had to fight against Indians who attacked them . Their journey was long and hard and dangerous , but they hoped to finally set up a new home and find enough to live on .