Civil War: Immigration and civil war can be linked in a variety of ways. In some circumstances, immigration may contribute to civil war, and in others, civil war may lead to increasing immigration. The establishment of ethnic or religious enclaves inside a country is one way that immigration might contribute to civil conflict. These enclaves may become disenfranchised and marginalised if they are not incorporated into greater society and do not have equal access to resources and political power. This can lead to tensions and disputes that could lead to civil war. Civil conflict, on the other hand, may result in increased immigration as individuals flee violence, persecution, and economic hardship in their own nations. In rare situations, migrants may seek asylum in neighbouring or distant nations. Receiving countries may face both humanitarian and political issues as a result of this. It is crucial to remember that immigration and civil war are both complicated and varied concerns, and their interactions can vary based on the environment and conditions.

Dakota War of 1862:  The Dakota War of 1862 was fought in Minnesota between the United States and various bands of Dakota (also known as Sioux) Native Americans. The battle was caused by a variety of factors, including tensions between Dakota people and American settlers, broken treaties, and disputes around the withholding of government annuities. While the war was primarily fought between the Dakota and the United States government, some immigrant settlers were involved on both sides. Some immigrant settlers sympathised with the Dakota cause and backed their efforts to oppose U.S. government policies, while others were seen as adversaries by the Dakota and were slaughtered or captured. Following the war's conclusion, the United States government tried and executed several hundred Dakota men for their involvement in the conflict. Many Dakota people were also evicted from Minnesota and relocated to reservations across the country. Overall, the Dakota War of 1862 was a terrible and complex war involving a variety of historical and cultural causes, including the experiences of the region's Native American and immigrant groups.

Spanish-American War: Immigrants had a key part in the Spanish-American War in 1898. Tensions between the United States and Spain emerged as a result of the latter's colonial possessions, particularly Cuba, which was struggling for independence from Spain. Many immigrants, particularly those from Cuba and Puerto Rico, were emotionally invested in the war's result. Cuban immigrants organised and pushed the United States government to intervene in the war and defend their fellow Cubans. Meanwhile, Puerto Rican immigrants were divided over whether the United States should annex Puerto Rico or leave it alone. During the war, immigrants served in large numbers in the United States military. Soldiers and sailors came from all walks of life, including Irish, Italian, Jewish, and African American families. Despite facing discrimination and poor treatment within the military, these immigrants played a critical role in the eventual US victory. Overall, the Spanish-American War had a tremendous impact on the relationship between immigrants and the United States, particularly in terms of how immigrants were perceived by American society as a whole. The conflict aided in the establishment of the United States as a global power and as a destination for immigrants seeking a better life.

World War I: Immigrants had an important part in WWI, both as troops and civilians. Many European immigrants, particularly those from Germany and Austria-Hungary, found themselves on opposing sides of the conflict from their new country. As a result, they were treated with suspicion and hostility, and many were subjected to persecution, monitoring, and detention. Immigrants, on the other hand, played an important role in the war effort. Hundreds of thousands of immigrants served in the military in the United States, for example, often alongside native-born soldiers. Many of these immigrants were keen to display their patriotism to their new country and their dedication to the cause of democracy. Immigrants were also key players in the war industries, working in factories and other sectors that aided the war effort. In many cases, immigrants were able to obtain higher-paying positions in the war industries than they had in earlier occupations. Overall, immigrants' experiences during World War I were complex and varied. While many faced prejudice and suspicion, others found opportunities for service and advancement. The war also had a significant impact on worldwide human movement, displacing millions of refugees and migrants.

World War II: Immigrants played an important part in WWII, both as warriors and civilians. Many immigrants fought for their adopted countries, including the United States, the United Kingdom, Canada, and Australia. During World War II, immigrants and their children made up a sizable component of the military in the United States. During the war, for example, around 500,000 Hispanic Americans participated in the United States armed services. Furthermore, more than 300,000 Mexican citizens came to the United States as part of the Bracero Programme to work in agriculture and other industries to help with the war effort. Immigrants from the Commonwealth, including India, Pakistan, and the Caribbean, served in the British military as well. The No. 303 Polish Fighter Squadron, which was exclusively formed of Polish pilots, played an important role in the Battle of Britain, and thousands of Jewish refugees from Nazi-occupied Europe joined the British armed forces. During World War II, immigrants also played an important role on the home front. They worked in factories, shipyards, and other important industries to the war effort. During the war, for example, thousands of Japanese Americans were forcibly transferred and incarcerated, but many chose to fight in the United States military, including the highly decorated 442nd Regimental Combat Team, which was virtually exclusively made of Japanese American soldiers.