When Stargate technology became commonplace, the main Earth stargate, Stargate One wasn’t able to handle the traffic. So it was decided to build stargates at all five Earth-Sun LaGrange points and reserve Stargate One for emergencies and government traffic. All of these LaGrange Points by this time had satellites, research stations and in two cases, orbital colonies; but despite some resistance the new gates were built. The Gateway Project opened up the inner solar system to a much larger amount of traffic and are the main transfer points for commercial traffic. Numbered G-1 thru G-5 they today include extensive nearby habitats, commercial and shipping facilities and two or more gates each.
G-1 and G-2 are by far the most important. Close to the Earth-Luna system they are called the Columbus and Gagarin Gates respectively and mostly handle in-system traffic. Travel time sublight to and from Earth from here is measured in minutes, though due to speed and traffic control restrictions it can usually take around an hour. G-3 is opposite to Earth and mainly serves as a transfer point between the outer planets, though it does handle outsystem traffic for Mars and Venus. Due to its lesser stability, it doesn’t support extensive space stations. It is called the Shen Ku Gate. G-4 and G-5 are the major transfer points for ships departing to or arriving from outsystem and then Earth, Mars, or Venus. The Io Transfer Point at Jupiter mostly handles outsytem trafffic for the outer planets. G-4 is called the Shackelton Gate, and G-5 the Tycho Gate. Sublight travel from here is usually a casual two-hour flight.