Before European settlement the coyote was largely a western animal. Wolf eradication removed both a competitor and a direct killer of coyotes, and land clearance created the edge habitat coyotes exploit. Colonisation of the east then proceeded on two fronts, north of the Great Lakes and south of them, reaching the Atlantic seaboard during the twentieth century.
Control efforts did not stop it. Coyote populations show compensatory reproduction: where mortality is high, litter sizes tend to rise, more young females breed, and pup survival can improve as competition falls. The effect is well enough documented that many wildlife agencies now describe indiscriminate removal as ineffective for reducing coyote numbers.
The eastern coyote carries a further complication. Genetic work shows that animals in the north-east are admixed, carrying wolf and domestic dog ancestry alongside coyote, and they average larger than western coyotes. Whether that population deserves separate species status is disputed, and the popular name coywolf compresses a more tangled history than it implies.