However, over the years the German population grew until Germans became one of the two main ethnic groups in the city. While other groups—such as Hispanics and African Americans—have become more prominent over the years, many living in Dubuque are descendants of German and Irish immigrants. The Civil War A number of people living in Dubuque served their nation in this war. A few of these people went on to play an important role in government. David Bremner Henderson (1840–1906) was a Representative in the US House, and was Speaker at the turn of the century. He was wounded in the war and lost a leg. William Boyd Allison (1829–1908) also served in the war. Afterwards, he later served in both houses of Congress. Allison Henderson park on the corners of University Avenue and Grandview Avenue is named for the two men. A few Dubuque citizens found themselves in trouble with the government during the war. George Wallace Jones (1804–1896) was imprisoned on a charge of disloyalty based upon correspondence with Jefferson Davis. Newspaper publisher Dennis Mahony was also imprisoned for several months in 1862 for editorials that were critical of the government. Many Catholics and immigrants in Dubuque were opposed to the Republican party because parts of the Know Nothings movement who had harassed them had been absorbed into the Republican party. It caused trouble for both groups when the President and other government officials misinterpreted this opposition as disloyalty. This was responsible, in part, for Dubuque becoming a stronghold for the Democratic party. After the Civil War The years following the war were ones of growth and expansion for Dubuque. When the Milwaukee Railroad Shops opened in Dubuque, a population explosion occurred when a number of young German families moved to the area in search of jobs. Lead mining no longer played a central role in the city. Now Dubuque was becoming a transportation center due to its position on the Mississippi River. Also, the lumber industry had a large presence in Dubuque. The Ku Klux Klan was an unwelcome presence at times in the area. In the 1920s, at the height of its power, Klan influence became visible in the area. Several crosses were burned in the area over an 18-month time period. One Klan meeting near the Center Grove section of the city degenerated into a huge fight when anti-klan demonstrators attacked Klan members. In 1925,