Final answer:
The Populist Party was most successful in the Western and Southern states in 1892, achieving notable state-level victories and securing several seats in Congress.
Step-by-step explanation:
The Populist Party had its most significant successes in the Western and Southern states during the 1892 election. This emergent political force secured five U.S. Senate seats, gained representation in the U.S. House of Representatives, and achieved multiple state-level victories. In the 1896 presidential election, they supported Democratic candidate William Jennings Bryan who advocated for the silver standard which favored the farmers' interests. Despite wins in states like Idaho, Nevada, Colorado, and Kansas, broader national challenges such as the urbanization of the population and a recovering economy weakened the Populist Party's influence.