The United States is the fourth largest country in the world, with a land area of about 9,000,000 square kilometers. With such a vast area to cover and protect, it’s no surprise that there are concerns over border security. If you read the news or watch it often enough, you might think that the only type of immigration we have in America is illegal immigration. There are many reasons why someone may choose to come to America without following the legal channels for doing so – from war and political unrest in their home country to grinding poverty. But what do we know about illegal immigration into America? How big a problem is it really? Do you need a green card if you want to stay here indefinitely as an immigrant? Let’s take a closer look at border control in the US and the illegal immigration problem.