Sales tax in McHenry County starts at 7.25% on general merchandise in unincorporated areas and climbs to 8.50% or higher inside home rule cities like Crystal Lake and Woodstock. The total is built from an Illinois state tax, a Regional Transportation Authority tax, a county Mental Health Board tax, and whatever your municipality has added on top. Groceries are a separate story since January 1, 2026, and so are drugs, medical appliances, and vehicles.
How the Base 7.25% Is Built
Three layers apply to general merchandise before any city tax enters the picture.
- The State of Illinois Retailers’ Occupation Tax of 6.25%.1Illinois General Assembly. 35 ILCS 120/2-10 – Rate of Tax
- The Regional Transportation Authority tax of 0.75%, which funds Metra, Pace, and regional transit. The statute names DuPage, Kane, Lake, McHenry, and Will counties at this rate.2Illinois General Assembly. 70 ILCS 3615 – Regional Transportation Authority Act
- The McHenry County Mental Health Board tax of 0.25%, approved by voters to replace the Mental Health Board’s former property tax levy and fund behavioral health services countywide.3McHenry County, IL. Mental Health Board Sales Tax a Success
Together those three add to 7.25%. Shop at a store in an unincorporated part of the county with no municipal overlay, and 7.25% is what you pay. The county’s quarter-cent is authorized under state law allowing county boards to impose sales taxes in quarter-percent increments for public safety, mental health, and similar purposes, after voter approval.4Illinois General Assembly. 55 ILCS 5/5-1006.5 – Special County Retailers Occupation Tax for Public Safety, Public Facilities, Mental Health, Substance Abuse, or Transportation
Why Your City Changes the Total
Home rule municipalities can stack their own sales tax on top of the 7.25% base in quarter-percent increments, with no cap on how high the local layer can go.5Illinois Department of Revenue. Home Rule and Non-Home Rule Sales Taxes That is why the general merchandise rate shifts noticeably across town lines.
Crystal Lake, the county’s largest city, adds a 1.25% home rule tax for a total of 8.50%.6Crystal Lake, IL. Transparency Portal Woodstock also reached 8.50% as of January 1, 2026. Algonquin has been at 8.00%, reflecting a 1.00% home rule add-on.7The Village of Algonquin, IL. Taxes and Fees Smaller communities fall at various points along that range. If you are making a large purchase, the Illinois Department of Revenue’s tax rate finder will give you the exact combined rate for any address in the county.
Groceries After the 2026 Change
Illinois eliminated the 1% state sales tax on most grocery items on January 1, 2026. Food for human consumption sold for off-premises eating is now exempt from the state Retailers’ Occupation Tax.1Illinois General Assembly. 35 ILCS 120/2-10 – Rate of Tax The exemption does not cover alcohol, soft drinks, candy, food infused with cannabis, or food prepared for immediate consumption like deli meals and restaurant takeout. Those remain taxed at full general merchandise rates.
The same legislation allowed municipalities and counties to impose their own 1% local grocery tax by ordinance.8Illinois Department of Revenue. FY 2026-11, Municipal and County Grocery Occupation Tax Rate Some McHenry County communities took that option. Algonquin’s 1% municipal grocery tax carries forward, so qualifying groceries bought there are taxed at 1.75% once the RTA tax is added.7The Village of Algonquin, IL. Taxes and Fees In towns that did not adopt a local grocery tax, qualifying groceries carry only the RTA’s 0.75% and the Mental Health Board’s 0.25%, for a total of 1.00%.
Drugs and Medical Appliances
Prescription and nonprescription drugs, medical appliances, insulin, and diabetic supplies are taxed at a 1% state rate rather than 6.25%.1Illinois General Assembly. 35 ILCS 120/2-10 – Rate of Tax Local taxes from the RTA, the Mental Health Board, and any home rule city can still apply on top of that 1%, so the total is lower than general merchandise but not zero.9Illinois Department of Revenue. What Is Significant About Retail Sales of Qualifying Drugs and Medical Appliances
Vehicles
Titled property follows different rules. Tax on cars, trucks, motorcycles, and trailers is based on where the buyer lives, not where the dealer is located. Live in Crystal Lake and buy from a dealer in Cook County, and you pay the Crystal Lake rate. The RTA tax applies to vehicles bought by McHenry County residents, but home rule municipal taxes generally do not apply to titled property.4Illinois General Assembly. 55 ILCS 5/5-1006.5 – Special County Retailers Occupation Tax for Public Safety, Public Facilities, Mental Health, Substance Abuse, or Transportation That gap is why the total you pay on a car can be lower than the sticker-rate math at a general merchandise store would suggest.
Use Tax on Out-of-State Purchases
When you buy something from an out-of-state retailer who does not collect Illinois sales tax, you owe use tax directly. The state rate is the same 6.25% that applies to general merchandise. You get credit for any sales tax already paid to another state on the same item, so you owe only the difference.
If your total use tax liability for the year is $600 or less, you can report it on your Illinois individual income tax return (Form IL-1040). Above $600, you file Form ST-44 and pay by the last day of the month following the purchase.10Illinois Department of Revenue. ST-44, Illinois Use Tax Return Instructions Most online purchases from major platforms already include Illinois tax at checkout, so the amounts individuals actually owe tend to be small, but the obligation exists.
Buying for Resale or as a Nonprofit
Two situations fall outside the regular consumer rate. A business buying inventory for resale pays no sales tax on those purchases, but it has to give the seller a signed Certificate of Resale (Form CRT-61) listing its Illinois account ID, a description of the goods, and a certification that the items are genuinely for resale.11Illinois Department of Revenue. Certificate of Resale Using a resale certificate on items you actually keep or consume can bring penalties, interest, and criminal exposure.
A qualifying nonprofit organized exclusively for charitable, religious, or educational purposes can apply to the Department of Revenue for a Sales Tax Exemption Identification Number, often called an E-number, using Form STAX-1. Approval can take up to 90 days and is not retroactive. Federal 501(c)(3) status alone does not qualify the organization; the Department makes its own determination.12Illinois Department of Revenue. Information for Exclusively Charitable, Religious, or Educational Organizations