Chicago Transit Authority
operator of mass transit in Cook County, Illinois
The Chicago Transit Authority (CTA) is a public transit agency in Chicago, Illinois, United States and one of the three service boards of the Northern Illinois Transit Authority (NITA). It operates the Chicago "L" rapid transit system and CTA bus services.
The CTA was established as an independent governmental agency by the Metropolitan Transportation Act passed by the Illinois General Assembly on April 12, 1945. It started operations on October 1, 1947, upon the purchase and combination of the transportation assets of the Chicago Rapid Transit Company and the Chicago Surface Lines streetcar system. In 1952, CTA purchased the assets of the Chicago Motor Coach Company, resulting in a fully unified system. As of 2026, the CTA is one of the three service boards overseen by the Northern Illinois Transit Authority (NITA), along with Metra commuter rail and Pace Suburban Bus.
In 2025, the system had a ridership of 319,160,900, or about 1,101,600 per weekday as of the second quarter of 2026.
History
The CTA was formed through the Metropolitan Transportation Act passed by the Illinois General Assembly on April 12, 1945. It started operations on October 1, 1947, upon the purchase and combination of the transportation assets of the Chicago Rapid Transit Company and the Chicago Surface Lines streetcar system. Over the next few years CTA modernized the "L", replacing wooden cars with new steel ones and closing lightly used branch lines and stations, many of which had been spaced only a quarter-mile apart.
The public source identifies “Chicago Transit Authority” as operator of mass transit in Cook County, Illinois. This brief keeps that definition visible, then builds a research path around Chicago, Transit and Authority.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Chicago Transit Authority”, the useful work is to connect “operator of mass transit in Cook County, Illinois” to the records capable of establishing context and consequence.
Maps, plans, fabric surveys and administrative records can establish how the site’s name, extent and function changed over time. The source revision retrieved here is dated Sep 19, 2026. The linked authority identifier is Q117309. VIAF identifies the subject as 121569986. The Library of Congress control number is n50048937. 3 of 4 selected statements include explicit references; 1 carry qualifiers and 0 use preferred rank. The first chronological checks are 1945, 1947, 1952 and 2026.
Architectural summaries often privilege surviving fabric and can understate demolished phases, contested use or displaced communities. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Treat names, boundaries and functions as historically changeable. Maps, plans, inventories and administrative records can clarify what the place meant at different dates.
- Historic place names
- Jurisdictional context
- Routes into maps and plans
Contemporary maps, plans, listed-building records, estate papers and the responsible local or national archive.
Three-step research path
- Establish the record: confirm the title “Chicago Transit Authority”, its source revision and the description used here.
- Expand the search: follow Chicago Transit Authority primary sources, Chicago Transit Authority archive and Chicago research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Chicago Transit Authority”?
- Which authority defined the place, boundary or structure at the relevant date?
- Which earlier names or jurisdictions may reveal additional records?
Search terms from this dossier
This entry incorporates text from “Chicago Transit Authority” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.