High Quality Content by WIKIPEDIA articles! Racial tension in Omaha, Nebraska mostly occurred because of the city's volatile mixture of high numbers of new immigrants from southern and eastern Europe and African American migrants from the Deep South. While racial discrimination existed at several levels, the violent outbreaks were within working classes. Irish Americans, the largest and earliest immigrant group in the 19th century, established the first neighborhoods in South Omaha. All were attracted by new industrial jobs and most were from rural areas. There was competition between ethnic Irish, European immigrants, and African American migrants from the South, for industrial jobs and housing, and strains in adjusting to industrial demands, unmitigated by organized labor in the early years. Some of the early labor organizing resulted in increasing tensions between groups, as later arrivals were used as strikebreakers.