People migrate for several reasons. These reasons may fall under these four areas: Environmental, Economic, Cultural, and Socio-political. Within that, the reasons may also be ‘push’ or ‘pull’ factors.

Push: 
Push factors are those that force the individual to move voluntarily, and in many cases, they are forced because, the individual risk something if they stay. Push factors may include conflict, drought, famine, or extreme religious activity.

Low economic activity and lack of job opportunities are also big push factors for migration. Other push factors include race and discriminating cultures, political intolerance, and persecution of people who question the status quo.

Pull:
Pull factors are those factors in the destination country that attract the individual or group to leave their home. Those factors are known as place utility, which is the desirability of a place that attracts people. Better economic opportunities, more jobs, and the promise of a better life often pull people into new locations.

Sometimes individuals have ideas and perceptions about places that are not necessarily correct but are pull factors for that individual. As people grow older and retire, many look for locations with warm weather, peaceful and comfortable locations to spend their retirement after a lifetime of hard work and savings. Such ideal places become pull factors too.

Very often, people consider and prefer opportunities closer to their location than farther away. In the same vein, people like to move to places with better cultural, political, climatic, and general terrain in closer locations than locations farther away. It is rare to find people move over very long distances to settle in places that they have little knowledge about.

An immigrant is always crossing an international border and looking for permanent residency in another country