It is Crataegus monogyna, the oneseed hawthorn, aka: English hawthorn. This plant has become quite the pest out in California, but it seems to have made inroads throughout the West as well as the East. According to the range map I saw, the middle of the US seems to be free of this invasive so far.
Crataegus are deciduous trees and shrubs, usually with spiny branches, lobed or toothed leaves, and clusters of creamy white flowers followed by red or black fruits. The berries are of particular high ecological value which provide nutrition for many small mammals and birds.
The Hawthorn is native to Ireland and its genus name Crataegus, from the Greek kratos, which means strength, is thought to be a reference to the hardness of the hawthorn's wood.
Common hawthorn is a rich habitat for all kinds of wildlife, from Hawthorn shield bugs and Yellowhammers that feed on the haws, to Wood mice and Slow worms that shelter in the thorny thickets.. . . . .364011235352!]0000000000000009783314144646!]