Colorado
A dated list of changes to how Americans vote: district maps, polling places and drop boxes, voting laws and rules, and courts and election officials. Each entry says who did what and when, shows what became of it, and links to the page it rests on. Attempts that failed are listed as failed. Entries that rest on a news report name the outlet.
This is the state view: events recorded for Colorado, then national events that apply here. See the national timeline.
In Colorado
2026
-
Colorado Supreme Court reverses the Title Board on proposed congressional redistricting initiatives
On June 29, 2026, the Colorado Supreme Court reviewed Title Board actions on several 2025-2026 initiatives about congressional redistricting. It concluded that Initiatives #240 and #327 "encompass multiple subjects," and that an initiative whose effect is conditioned on passage of a separate initiative violates the single subject requirement, as to Initiatives #241, #242 and #328 (affirming as to #328 the Board's decision not to set a title).
- Williams v. Nathan (Initiatives #240 and #327), No. 26SA126 (Colo. June 29, 2026) ↗
- In re Title Board: Initiatives #241, #242 and #328, Nos. 26SA122, 26SA123, 26SA157 (Colo. June 29, 2026) ↗
Source last checked Oct 24, 2026
2021
-
Colorado Supreme Court approves state Senate and House maps drawn by the independent commission
In an original proceeding under article V, section 48.3, the Colorado Supreme Court reviewed the Senate and House plans adopted by the Colorado Independent Legislative Redistricting Commission. It concluded that "the Commission did not abuse its discretion" and approved the plans, ordering them filed by December 29, 2021.
Source last checked Oct 24, 2026
-
Colorado Supreme Court approves the independent commission's congressional map
In the first review under Amendment Y, the Colorado Supreme Court wrote that "the Commission did not abuse its discretion in applying the criteria in article V, section 44.3 in adopting the Plan on the record before it." The court approved the plan for the ensuing decade and ordered it filed with the Secretary of State by December 15, 2021.
Source last checked Oct 24, 2026
Nationwide
2026
-
Census Bureau proposes residence criteria for the 2030 census that would exclude some noncitizens from the apportionment count
On September 10, 2026 the Census Bureau, an agency of the Department of Commerce, published a proposed rule in the Federal Register (91 FR 57524, Docket No. 260903-0005, RIN 0607-AA75) that would add two new parts to the Code of Federal Regulations: residence criteria for the decennial census, and standards and restrictions for demographic questions on the census questionnaire. On residence, the notice states that "the Census Bureau proposes to include lawful permanent residents within the apportionment base, while excluding from the apportionment base illegal aliens and aliens whose legal status is less durable and indefinite in length than lawful permanent resident status," and says it is considering using administrative records to determine legal status. The comment period, first set to end October 13, 2026, was extended to November 2, 2026 by a notice published October 5, 2026. Al Jazeera and CNBC reported on the proposal, and CNBC reported that opponents expect litigation.
- Decennial Census of the Population of Americans; Proposed Residence Criteria and Proposed Regulations for Demographic Questions, 91 Fed. Reg. 57524 (Sept. 10, 2026) (GovInfo) ↗
- Same proposed rule, extension of comment period, 91 Fed. Reg. 63207 (Oct. 5, 2026) (GovInfo) ↗
- Trump administration proposes excluding certain immigrants from US census (September 10, 2026) ↗ News report, Al Jazeera
- CNBC report on the proposed 2030 census rule (October 13, 2026) ↗ News report, CNBC
Source last checked Oct 22, 2026
2021
-
Census Bureau releases 2020 redistricting data for states
On August 12, 2021, the Census Bureau released the 2020 Census Redistricting Data (Public Law 94-171) Summary File, which it described as delivering data for states to begin redistricting. On September 16, 2021, it released the same data in an easier-to-use format on data.census.gov and delivered a toolkit to states.
- Census Bureau press release CB21-CN.55, August 12, 2021 ↗
- Census Bureau press release CB21-CN.63, September 16, 2021 ↗
Source last checked Oct 22, 2026
-
Census Bureau announces 2020 Census apportionment results
On April 26, 2021, the Census Bureau announced that the 2020 Census resident population of the United States on April 1, 2020 was 331,449,281, and that Commerce Secretary Gina Raimondo delivered the population counts used for apportionment of the U.S. House to the President.
Source last checked Oct 29, 2026
How this timeline is built
Every entry rests on at least one source that was opened and read, and that source states the date and the fact. Courts, legislatures, election offices, the Justice Department, the Census Bureau, the Federal Register and Congress.gov come first. A news report is used only when no official page states the fact, and it is labeled with the outlet's name. Encyclopedias are not used as sources. History starts in 1965 with the Voting Rights Act. County names come from the Census Bureau's 2024 Gazetteer. Congressional district numbers are those in use for the 2026 election; an event is tagged to a district only when its source names that congressional district.
When a later event changes an earlier one, such as a law later struck down, both entries are listed and point to each other. This page does not predict outcomes or say which party a change helps. U.S. House maps for 2026 · How people voted in past elections, by county · Back to the 2026 voting center.