The Colorado State Senate is the upper house of the Colorado General Assembly, the state legislature of the US state of Colorado. It is composed of 35 members elected from single-member districts, with each district having a population of about 123,000 as of the 2000 census. Senators are elected to four-year terms, and are limited to two consecutive terms in office. Senators who are term-limited become eligible to run again after a one-term respite.