While such cross-pollination has occurred throughout the history of both genres, the term is usually used to refer to the wave of groups of the late 1960s and early 1970s who began to record country flavored records, including Neil Young, The Byrds, Gram Parsons and Bob Dylan with The Band.
The term is also used for those who came after them, such as Lynyrd Skynyrd and The Eagles, and the many bands they influenced, such as the alternative country movement.
Bands that could be considered country rock include:
The Allman Brothers Band, a jam band with bluegrass influences
The Band
Blue Rodeo
The Byrds
The Eagles
Flying Burrito Brothers
Kinky Friedman
Grateful Dead, a psychedelic band with bluegrass influences
Lynyrd Skynyrd
Michael Nesmith
Neil Young, a diverse artist whoes music spans many other genres as well
Gram Parsons
Poco
Linda Ronstadt as produced by Peter Asher and John David Souther
Sir Douglas Quintet