Every Gallon in Marengo Carries About a Dollar in Tax. Here Is Where It Goes.

A reader asked us a question plenty of people have been asking at the pump this year: how much of what I pay for gas is tax, and is Marengo worse than the next town over?

The short answer: at this week's average price in McHenry County, about $1.09 of every gallon is tax. About 8 cents of that stays with the City of Marengo. And depending on which way you drive, the same gallon carries anywhere from about 13 cents less tax (Genoa) to about 11 cents more (Chicago). Between Marengo, Woodstock and Crystal Lake, the difference is a few cents at most, and Marengo's taxes are the lowest of the three. A bigger gap than that at the pump is not the tax.

Prices have given people reason to ask. AAA put Illinois' average for a gallon of regular at $4.63 on September 16, up from $3.44 a year earlier. The McHenry County average that day was $4.62, and that is the price we use for the math below.

What Is Inside a $4.62 Gallon

Every gallon carries five layers of tax, and all of them are built into the price on the pump.

The first four are flat amounts per gallon, so they cost the same whether gas is $3 or $5. Sales tax is the one that moves with the price. Illinois is one of at least 11 states that charge a sales tax, or something like one, on gas, according to the Commission on Government Forecasting and Accountability, the General Assembly's research office.

How that sales tax is figured has a wrinkle. State rules let stations leave the state's own 48.3-cent tax out of the price they figure sales tax on, because that tax is legally a tax on the driver. The federal tax, the county's tax and the tank-cleanup charges stay in. So the familiar complaint that Illinois charges tax on a tax is half true. There is also a small break for E15, the blend with 15% ethanol: through 2028, the state taxes it on 90% of its price, which works out to about 3 cents less tax on a gallon at the same price. Ordinary regular gas, which is almost always blended with 10% ethanol already, does not get that break.

Marengo's 8.5% sales tax is itself a stack:

• 6.25%, the statewide rate. Five points of it go to the state, 1 point comes back to Marengo and a quarter point goes to McHenry County.
• 1%, the regional transit tax, which funds Metra, Pace and the CTA across the six Chicago-area counties.
• 0.25%, McHenry County's mental health tax. County voters approved it in March 2024, and the county dropped the Mental Health Board's property tax levy in exchange, as the Northwest Herald reported.
• 1%, Marengo's own sales tax. City voters approved it on March 19, 2024, and it replaced the city's vehicle stickers: in November 2023 the council voted to repeal the sticker tax if, and only if, the sales tax passed. The same night, the council passed a resolution saying it intended to spend the money on road and sidewalk work in the city.

Put it all together and the $1.09 splits like this:

The state sends part of its share back to local governments, including Marengo, as explained below.

Why Illinois Runs High

For almost 30 years, Illinois' gas tax sat at 19 cents a gallon. In 2019, the Rebuild Illinois capital program doubled it to 38 cents and tied it to inflation, so it normally rises every July 1. It has climbed to 48.3 cents since.

Add the statewide sales tax and Illinois ranks near the top of the country. The Tax Foundation, a Washington tax research group, put Illinois' state taxes on gas at 70.4 cents a gallon as of July, second only to California's 73.6. Indiana was third at 63.1. Wisconsin, a short drive north, was 32.9. Those figures leave out local taxes, which is where Marengo's county and city layers come in.

Marengo Has No Gas Tax of Its Own, and Cannot Add One

The one thing Marengo does not charge is a per-gallon tax of its own, and state law does not let it. Illinois allows home rule cities to set their own gas taxes, and towns in Cook County may add up to 3 cents. A city of Marengo's size outside Cook County, without home rule, has no such power. (If home rule is new to you, our explainer from July covers it.)

Some neighbors with home rule do use it. Woodstock has charged 3 cents a gallon since April 2020, to pay off the bonds from its 2020 street program, according to the city's current budget. Belvidere has charged 2 cents a gallon since 2018, under its city code. Chicago charges 8 cents on top of Cook County's 6. Huntley, which also has home rule, has no gas tax in its code.

Marengo's lever on gas is the sales tax: the 1% that voters approved in 2024, which took the place of the annual city vehicle sticker, applies to gas like almost everything else sold in town. City staff told the council in October 2023 that the stickers were netting about $16,000 a year after the cost of running the program.

How Marengo Compares

Here is the same $4.62 gallon, taxed at the rates in effect in each place.

Four things explain nearly all of the differences:

• Town lines. Union and any station outside a town's limits skip Marengo's 1% city sales tax, which is worth about three and a half cents a gallon at this price. Union has no gas station of its own, so its row shows what a gallon sold there would carry. Harvard and the McHenry County side of Huntley charge the same 1% Marengo does.
• County lines. Kane County's gas tax is 8 cents, a bit under McHenry's 8.7, and Kane has no mental health sales tax. That puts Hampshire and Huntley's south side about a penny and a half lower.
• The edge of the transit region. Boone, DeKalb and Winnebago counties are outside the six-county transit district, and state law gives them no county gas tax. That is why Belvidere, Rockford and Genoa come out about 8 to 13 cents lighter, even with local sales taxes of their own.
• Home rule. Woodstock's 3-cent gas tax and higher city sales tax make it the heaviest of the McHenry County towns on this list. Chicago stacks a city gas tax, a county gas tax and a 10.5% sales tax.

On a 15-gallon fill-up in Marengo, taxes come to about $16. The same tank carries about 50 cents less just outside town, about $2 less in Genoa and about $1.60 more in Chicago.

A Big Gap at the Pump Is Not the Tax

This is the part worth remembering. Between Marengo, Woodstock and Crystal Lake, nearly everything government controls is the same: the same federal tax, the same state tax, the same county tax and the same federal clean-air rules for the gas itself. The one difference is local, and it runs in Marengo's favor. A gallon in Crystal Lake carries about a penny more tax than one in Marengo, and a gallon in Woodstock about 3.6 cents more.

So if you see gas 30 or 50 cents a gallon cheaper in Woodstock or Crystal Lake, taxes are not the reason, and no government body set that difference. It comes from the rest of the price: what each station paid for its fuel, what it costs to run the business and what it charges. None of that is set by government.

Taxes do explain part of the gap with Belvidere, Rockford and Genoa, about 8 to 13 cents. Even there, the county averages sit within about a nickel of each other: AAA's figures for September 16 put McHenry at $4.62, Boone at $4.60 and DeKalb at $4.57.

What Changed This Summer

Four changes took effect in July and August, and they did not all point the same way.

• The state skipped its July increase, for now. This year's inflation adjustment was 2.68%, which would have taken the state tax to 49.6 cents. A state revenue law signed June 16 froze it at 48.3 cents through December 31 instead.
• The transit tax went up a quarter point on August 1 in all six Chicago-area counties, taking Marengo's sales tax from 8.25% to 8.5%. The regional transit board approved the increase at its first meeting under the state's new transit law, according to reporting by WBEZ and the Chicago Sun-Times. At current prices it adds just under a penny a gallon.
• County gas taxes moved. McHenry County's rose from 8.5 to 8.7 cents on July 1 under the inflation formula in state law. Kane County raised its rate from 5 cents to 8.
• The state's share of the fuel sales tax changed hands. That share is about 19 cents of a $4.62 gallon. Until this summer, most of it went to the state's Road Fund. Starting July 1, state law sends most of it to public transit instead: 85% to the fund for the Chicago-area system and 15% to transit downstate.

What Comes Back to Marengo

The city sees gas tax money two ways.

The first is a share of the state's motor fuel tax. IDOT divides part of it among Illinois cities by population and sends it monthly. Marengo received about $348,000 over the last 12 months, roughly $46 per resident, based on its certified population of 7,568. That money arrives whether or not anyone buys gas in town, and it can only go to road work. This year's city budget puts it toward the last Prospect Street payments, road patching and payments on road bonds. (Our streets explainer covers those projects.)

The second is sales tax on gas sold here: the 1 point of the state rate that comes back to the city plus the city's own 1%, together about 7.6 cents a gallon at today's price. Some of it is paid by drivers passing through on Routes 20 and 23.

The state does not report sales tax by product, so we estimated the yearly total. The county gas tax collected at Marengo businesses in 2025 was $370,271, according to Department of Revenue records, which works out to about 4.4 million gallons of fuel sold in town. At last year's lower prices, the city's two 1% taxes on that fuel would have come to roughly $200,000 to $250,000. For scale, the city's budget projects about $800,000 this year from its 1% sales tax on all sales.

McHenry County's 8.7 cents, by state law, can only go to roads, paths and sidewalks.

So, to the reader's question: a gallon in Marengo is taxed about the same as one in Harvard or Huntley, a few cents more than one sold outside any town's limits in McHenry County, a few cents less than one in Woodstock or Crystal Lake, and about 8 to 13 cents more than one in Belvidere, Rockford or Genoa. About 8 cents of it goes to the City of Marengo, half of that through the sales tax that replaced vehicle stickers, which the council said it would spend on roads and sidewalks. If the price here runs well above the next town's, that gap is the station's price, not the government's tax.

Marengo Weekly reviewed Illinois Department of Revenue rate bulletins and its August 2026 sales tax rate file; the Motor Fuel Tax Law (35 ILCS 505/2) as amended June 16, 2026; the Retailers' Occupation Tax Act (35 ILCS 120/2-10 and 120/3) and the Use Tax Act (35 ILCS 105/3-40); the County Motor Fuel Tax Law (55 ILCS 5/5-1035.1); the Illinois Municipal Code (65 ILCS 5/8-11-1.3, 8-11-2.3 and 8-11-6a); Department of Revenue rules at 86 Ill. Adm. Code 130.435 and 130.2060; the federal reformulated gasoline area list at 40 CFR 1090.285; IDOT motor fuel tax allotment records through August 2026; Department of Revenue sales tax collections by business type for 2024 through mid-2026; the City of Marengo's council minutes and packets from October 2023 through April 2026; the Woodstock and Belvidere budgets and the Belvidere, Huntley and Crystal Lake city codes; the Commission on Government Forecasting and Accountability's 2026 Illinois Tax Handbook for Legislators; reports from the Tax Foundation and the Civic Federation; and AAA prices from September 16, 2026. Per-gallon figures are our arithmetic from those rates.