This term is given to the part of the United States that was the center of most of the nation's economic activity until the 1970s and 1980s, when companies began relocating to warmer, more economically profitable parts of the country.

The area that was the center of economic activity was known as the economic hotbed.

Explanation:

Until the 1870s and 80s when the slowdown and the downturn of the booming American economy started, most of  the production and economic activity was based around the bustling states that were known as the hotbeds .

These hotbeds were states like California that had a warmer, more pleasant climate all around the year and were the most strategically important parts of the country for their economic activity as companies worked from there.

especially research the treaty of greenville and the treaty of colerain in washington's administration.   also research at least one significant treaty from the administrations of adams, jefferson, and madison. tell the outcome of each treaty and how it did or did not in the further development of the west.

treaty of greenville (1814) the treaty of greenville (1814) was called a treaty of peace and friendship between the united states of america and the tribes of native americans called the wyandots, delawares, shawanoese, senacas and miamies.

the treaty of colerain was signed at st. marys, georgia in camden county, georgia, by benjamin hawkins, george clymer, and andrew pickens for the united states and representatives of the creek nation, for whom indian trader langley bryant served as an interpreter, on june 29, 1796, proclaimed on march 18, 1797, and codified as 7 stat. 56. colerain was a small community and the site of a u.s. indian factory founded by james seagrove.  

this treaty affirmed the binding of the treaty of new york (1790). the treaties of hopewell and the treaty of holston (1791) established boundary lines between the choctaws, chickasaws, cherokee, and the u.s. the treaty of colerain bound the creek nation to acknowledge the boundaries established in those treaties.  

it also established the boundary line between the creek nation and the united states. at the time of this treaty, the boundaries between spanish florida and the u.s. had not yet been established. this treaty formally allowed the creek chiefs to acknowledge the negotiation for delineating the georgia-florida boundary with spain.  

the treaty contained a provision that the president of the u.s. may establish a trading or military outpost.  

the united states demanded that the creeks give up their american prisoners and also return all "citizens, white inhabitants, negroes and property" taken by the creeks.  

the treaty describes when it would take effect. after the treaty had been signed but not yet promulgated, the u.s. senate requested modification of two articles of the treaty. the first modification stipulated that the military or trading posts would be under the control of the united states. the second modification stipulated that if the u.s. no longer required the use of those posts, the locations would revert to the creek people.