Geography affects the border security of the United States by making it difficult to keep the borders completely secure. This is true because of the topography and extent of the US’s land borders and because of the relative levels of development of the US and its southern neighbors.
Geography affects US border security because geography helps to bring many people who attempt to enter the US illegally. The United States is one of the richest and most developed countries in the world. To the south, it is neighbored by a number of countries that are much less wealthy and developed. This geographical fact means that many people from relatively poor Latin American countries want to enter the US. As so many people try to enter the US, border security becomes more difficult.
Geography affects US border security because the US’s borders are so long and because they extend across very difficult terrain. The “Lower 48” states of the US have two very long land borders, totaling roughly 6,000 miles. This means that it would be very hard to patrol all of the two borders. The difficulty of patrolling is exacerbated by the fact that the borders run through mountains, deserts, and forests. In this way, the length and rough terrain of the borders make it very difficult to maintain complete border security.
In these ways, geographical factors make it harder for the US to have complete border security.