What it is

Situs (Latin for “position” or “site”) is the location a transaction is legally assigned to for tax purposes. It answers a deceptively simple question: which jurisdiction has the right to tax this sale? For sales tax, the situs of a sale determines both the state that taxes it and the local jurisdictions — county, city, special district — whose rates stack on top.

Situs isn’t chosen at random. It’s the output of a state’s sourcing rules. Sourcing is the mechanism; situs is the result. Once a state’s rules tell you where a sale is sourced, that location is the situs, and the combined tax rate at that location is the rate you charge.

The general principle is that a sale’s situs is where the tangible personal property is delivered or where the service is performed. But because states write their own sourcing rules, the same shipment can have a different situs depending on which state’s rules govern.

Why it matters to a multi-state seller

For a multi-state seller, situs is what turns a stack of orders into the correct line on a return. Getting it wrong doesn’t just mean a slightly off total — it means tax remitted to the wrong jurisdiction, the wrong combined rate charged, and returns that don’t reconcile.

Combined rates vary block by block in many states. An Arizona or Colorado order delivered to one address can carry a different combined rate than the same order delivered a mile away, because the local situs differs. Charge the origin-city rate when the state sources to the destination, and you’ve collected the wrong amount on every order to that area.

Because nexus tells you whether you must collect in a state but situs tells you what rate and for which jurisdiction, the two work together: nexus opens the obligation, situs sizes it.

Worked example

Your business is located in Columbus, Ohio (origin), and ships a $1,000 order to a customer in Cleveland, Ohio (destination). The two cities sit in different counties with different combined rates.

Ohio sources most retail sales on a destination basis, so the situs of this sale is Cleveland, not Columbus. You charge the Cleveland combined state-plus-county rate — not your Columbus rate — and the tax is reported as Cleveland-jurisdiction tax on your Ohio return.

Now flip it. Your business is in an origin-based state and ships within that state. There, the situs is generally your ship-from location, so you charge your own location’s combined rate regardless of where in the state the customer sits. Same physical movement of goods, opposite situs — entirely because the two states use different sourcing rules.

State-level nuance

Situs is driven by whether a state is origin-based, destination-based, or mixed:

Two practical points. First, for interstate sales into a state where you have nexus, states almost universally apply destination-based sourcing — the situs is the buyer’s location — even if that state is “origin-based” for its own in-state sellers. Second, local situs matters as much as state situs: in home-rule and many destination states, you must resolve the sale down to the exact delivery jurisdiction to get the combined rate right. See origin vs. destination for how the two systems differ.

How this connects to staying compliant

Situs is where rate accuracy lives. The compliance workflow is: confirm nexus in a state, identify that state’s sourcing rule, assign each transaction its correct situs, apply the combined rate at that situs, and report the tax to the right jurisdiction on the return. A tax engine automates this only if it’s fed accurate ship-to addresses and the current rules.

Situs errors are insidious because they pass quietly until an audit. Under-collect by sourcing to a low-rate jurisdiction and the state assesses the shortfall; over-collect by sourcing to a high-rate jurisdiction and you owe refunds to customers. Either way, the fix starts with getting situs right at the point of sale.

Sources: Ohio Department of Taxation — Sales and Use Tax: Sourcing (ST 2009-03): https://tax.ohio.gov/wps/portal/gov/tax/business/ohio-business-taxes/sales-and-use/information-releases/st-2009-03-sourcing Sales Tax Institute — How to Determine Sales Tax Sourcing for Services: https://www.salestaxinstitute.com/resources/how-to-determine-sales-tax-sourcing-for-services Bennett Thrasher — What are Sales Tax Situs: https://www.btcpa.net/glossary/sales-tax-situs