Complex sentence: Growth in Redding during the sixties and seventies was also caused by Redding officials annexing a number of surrounding county areas, including an area east of the Sacramento river made up of the unincorporated community of Enterprise.
Split into simpler sentences: Growth in Redding during the sixties and seventies was also caused by Redding officials annexing a number of surrounding county areas. The places annexed included an area east of the Sacramento river, which was the unincorporated community of Enterprise.