What single event sparked the westward movement? why?

a. because the u.s. was the leading with the most technology, economy, etc. also was teamed with other allies witch boosted the economy and materials to improve technology and use it.

the second significant cause of the great migration was the desire of black southerners to escape segregation, known euphemistically as jim crow. rural african american southerners believed that segregation - and racism and prejudice against blacks - was significantly less intense in the north.