Asklemmy

There's a class of orbits called "polar orbits" that are sideways and perpendicular to the spin of the earth. These orbits are useful for satellites whose main job is taking pictures of earth, because they will cover nearly all of the earth's territory over time. You get into a polar orbit by launching to the north outer south.

Aside from that, nearly all launches go towards the spin of the earth, because it's a free boost. The fancy rocketry word for this is "prograde".

The sun appears to traverse from east to west in the sky. This means that the earth is moving the opposite way: west to east. So if you want to take advantage of the free boost, the rocket needs to take off in an easterly direction.

The amount of spin you get is greatest if you launch from the tropics near the equator, and it falls off at greater north or south latitudes. In theory, if you set up a launch pad at the north pole, the spin boost would be zero in all directions, because you're just rotating in place. At the equator, the free boost is around 1000 mph or 1600 km/hr.

So the ideal launch site is as close to the equator as possible, and it has low population off to its east, in case the rocket blows up or crashes. The United States has two sites that meet these criteria: one in Florida and one in extreme south Texas. Both of these face an ocean to the east. Europe launches Ariane rockets from French Guiana in South America. Russia uses Kazakhstan, which is on the southern ends of the old Soviet Union.