For westward expansion, the government did a lot of things:
- Provided protection against Indians (Army)
- Gave huge land grants to the railroads to get them to push westward
- Gave cheap land to settlers (Homestead Act)
- Helped figure out the best ways to farm (Land grant colleges)
These are the main things the government did to help settlers.
For industrial growth, mainly the government just didn't do anything to regulate the large companies. The government didn't impose any rules on things like child labor or minimum wage/maximum hours, things like that. They also tended to side with businesses against unions.
One can not under value the project that was the expansion of the rails westward in the post Civil War decade. This was considered a national imperative as well as the overriding mood of the populous of the east to expand with the "Manifest Destiny" Goods had to be made, sold and transported west from the smoke-filled cities of the East
Certainly this amount of material and hardware had to come from the fire-blast furnaces of the East and Mid-west. The role of law makers, politicians and government was at each small twist in this slow yet never-stopping westward encroachment. Park lands were delineated, Indians were displaced and moved, herds of the indigenous buffalo were governmentally exterminated and the country would have a new thriving product and vitality often because of these newly exploited and dwindling resources. Most raw supplies would be reworked into a multitude of things in the factories of Chicago, New York, Buffalo and Saint Louis.
In addition or even before some of the previously mentioned things like the Homestead Act...Land was acquired from Spain and France i.e Louisiana Purchase and the acquisition of Florida, california...