When you break down how the telecommunications system works within the United States, you may come across something called the LATA. This is something that helps keep the system working and working in proper order. LATA stands for ‘local access and transport area.’ At one time, AT&T controlled most of the phone service in the US, but when that was busted up to allow competition, the LATA was needed to represent geographical locations in relation to phone access and services.
The LATA information you can find is usually used to determine the area in which any phone company can offer their services. Generally speaking, a phone company is not really all owed to offer services that start in one LATA area but then ends in another. This was put in place with the intention of no one company forming a monopoly over the phone service in the US the way that AT&T had for so long. When the company was broken up, the LATA came into play.
If you were to look at a map of LATA information, you may notice that they seem to be the same areas that are covered with area codes. Though there is some truth to that, there are some that move beyond boundaries like state lines that otherwise contain where an area code is assigned. They were designed to be around certain markets and areas of population rather than to go by standard state lines and other like boundaries.
Though you may pay a flat fee (or nothing) for long distance today, you may remember how different the rates used to be when you called different places. This was all due to the LATA lines. Some rates were lower because they were within the same area, and some overlapped by state. This is what caused rates to fluctuate so much. Though it can seem complicated, you can think of LATA as a system put in place to keep competition going and hopefully, prices down. All systems need some sort of regulation and limits to keep things in check, and that is what the LATA is supposed to do.