A $5.7 billion extension of the Red Line to Chicago's Far South Side, a $4 billion rebuild of the Central Tri-State Tollway, two Fermilab megaprojects at Batavia, a new concourse rising at O'Hare and a $1.15 billion barrier against invasive carp at Brandon Road headline Illinois's public pipeline.
*How to read the total: the sum of the published figures in the list below. Bases differ by project — most are total cost estimates, some are federal grants, program totals, or construction contracts as awarded. Each project's expanded view labels its own basis. We add them up with the labels showing rather than pretend they're all the same kind of number.
Hover a pin for the project snapshot. Pin numbers match the project list below. Locations are approximate (nearest city or corridor midpoint) on a schematic state outline.
Click any project to expand its full record — description, owner, dates, funding, the law behind it, and its source. Filter by who owns it and where it stands, or sort by cost.
16 major public projects: 7 in Chicago and Cook County, 2 at Fermilab in Batavia, 2 in Springfield, 2 in Champaign–Urbana, 2 in the Metro East (Mascoutah and Scott AFB) and 1 corridor each in Will County and southern Illinois. The listed figures sum to ≈$20.9B. Illinois's list is majors-heavy — the state's published, firmly costed pipeline above $10M is dominated by very large transport and federal science projects, and smaller municipal work is comparatively thin in published figures. Two bi-state Mississippi River bridges that serve Illinois — the I-270 Chain of Rocks Bridge (≈$496.2M, shared 50/50 by Illinois and Missouri) and the Don Welge Memorial Bridge at Chester ($307.1M) — are listed once, at their joint totals, on Missouri's page and are NOT counted here; the new Lock & Dam 25 is likewise on Missouri's page. LBNF/DUNE's $3.3B total spans Illinois and South Dakota and is listed once, here, on its host laboratory's page.
How the big programmes are counted: only priced, funded construction is tallied. At O'Hare, only the $1.455B Concourse D guaranteed-maximum-price contract is listed — not the $8.78B ORDNext programme around it. On the Tollway, the I-490/IL 390 interchange is listed at its $536M project figure, not the $4.3B Elgin O'Hare Western Access programme; the Central Tri-State is listed at its published $4B corridor programme total, with its $800M I-290/I-88 interchange treated as a component. For CREATE, only the funded $427.6M 75th Street package in the federal grant agreement is tallied — the corridor's later segments are larger and only partly funded, and the $291M Mega grant for segment EW2a is separate money, disclosed on the record but not added. The CTA Red Line Extension is listed at the $5.7B total published at its Full Funding Grant Agreement and 2026 groundbreaking, superseding CTA's earlier $3.6B figure; its federal freeze and court-ordered restoration are on the record. Fermilab's two records do not overlap: the $3.3B LBNF/DUNE total excludes PIP-II's $978M.
News-flagged sources: seven rows rest on news or trade-press reporting of official figures, flagged 'news-flagged' in the data — the CTA Red Line Extension (Brief News, CTA / City of Chicago figures), LBNF/DUNE's CD-1RR total (DOE review, via Wikipedia's project summary), O'Hare Concourse D (Airport Industry News, Chicago Department of Aviation figures), the Springfield Rail Improvements total (Railway Age, USDOT / FRA figures), the Capitol north wing (Capitol News Illinois, Architect of the Capitol figures), UIUC's Altgeld/Illini budget (The Daily Illini, university Facilities & Services figures), the I-57/I-74 interchange (Construction Equipment Guide, IDOT figures) and the Scott AFB operations centre (the base's own release, via EIN Presswire). Each record names the underlying official source. The softest record on the page is LBNF/DUNE: a 2023 DOE cost-range estimate for a two-state project whose near-site scope is still being baselined in components.
Deliberately excluded: projects completed in a prior year, however large — O'Hare Terminal 5 expansion (2023), the CTA Red & Purple Modernization Phase One (completed 2025), the Jane Byrne Interchange rebuild (completed 2022), the I-74 Iowa–Illinois bridge (completed 2021), UIC's Computer Design Research & Learning Center ($129.8M, opened July 2025), Chicago Rockford airport's $50M cargo expansion (completed 2023) and the LaGrange Lock rehabilitation ($117M, completed 2020). Also excluded: the new 1,200-foot LaGrange Lock (NESP) — in design, without funded construction; the Illiana Expressway and the I-55 managed-lane P3 — unfunded proposals; the Obama Presidential Center — a private foundation project; and private or nonprofit builds of any size (data centres, hospitals, Boeing and Amazon facilities) — out of scope by rule.