What was a major push factor that increased immigration to the United States between 1830 and 1850?

A PUSH factor would be the Irish Potato Famine

Explanation:

For reference, a pull factor is something that is enticing about the area you want to move to. (ex: promise of land, money, glory, etc)

A push factor is something happening where you live that makes you not want to live there anymore. (Ex: famine, war, disease, religious persecution)

Here, it is important to note that improvements in ships and voyages would NOT be a push factor. Nothing is forcing people to leave their home. (A person would not want to leave just because the USA has ships.

A pull factor that is true to the time period would the the Potato famine that started around the 1840s, and affected Ireland, Northern Europe, etc.