1000 years ago, as Earth’s planetary ecosystem failed, several hollowed out asteroids were prepared as sub-light colonization ships, each holding between 100,000 and 200,000 carefully selected volunteers from several nations, the colonists in cold sleep as the ships travelled under computer control. The ships were capable of accelerating to about 50% of the speed of light and then decelerating in the target system, and multiple target systems were chosen, several of which were in the area surveyed by the Kepler Mission.
One ship, the Mayflower, with its multinational crew, set out for a star approximately 150 light-years away from the Sun, a star known to have an Earthlike planet in the Goldilocks zone. After 300 or so years of travel, the Mayflower arrived at a system which was then named after the captain of the ship, William Donnelly. Initially, the crew planned to colonize the main world as a mass effort, with each nationality settling an area of the world chosen by lots. As the world was being surveyed (and with only a fraction of the 150,000 colonists awake), however, a follow-up ship from Earth arrived with a small technical crew of 100 cold sleeping colonists, and bearing several technological advancements, the most significant of which was a prototype jump drive.
The jump drive was copied for further research, and the small ship (the Squanto) was sent to explore the nearby stars while the colonization of the target world, Donnelly, continued. Once the world was declared ready for colonization, the majority of the colonists were awakened, and they and their equipment and supplies ferried down to the planet by heavy landers.
As time passed, the original colony sites on Donnelly began to get crowded, and individual bands of people have split off, most using the heavy landers with newly installed jump drives to settle nearby star systems. The new colonies are national in nature, but little friction has been seen between the colonies--as far as anyone else knows, this could be the last bastion of humanity in the universe. (The Squanto left just before the Earth’s environment collapsed completely, and the other colonization ships’ crews have not been in contact with anyone hereabouts.)
Most worlds have a patrol, for search and rescue, and for handling smugglers or other scofflaws. More forceful security is handled by contract forces, called QRFs, based out of a deep space base in the Mississippi 0605 system, and using 2000 ton cruisers with Jump 4 and 5 Gee drives. The government of Donnelly hires the crews to handle problems, and that is that, as far as Donnelly is concerned.