The basic rule is that you withhold taxes based on where the work is physically performed, not where your business is located or where the employee lives. If you’re a Massachusetts company with an employee working from their home in Rhode Island, you need to follow Rhode Island’s payroll tax rules for that person.

Before you can legally pay someone in another state, you typically need to register for state income tax withholding and state unemployment insurance in that state. Some states like New Hampshire, Florida, and Texas have no state income tax, but you still need to register for unemployment insurance. Each registration comes with its own employer account number, filing schedule, and tax rates.

Each state has its own withholding tables and requirements. Some states accept the federal W-4 information while others require their own state withholding forms. Massachusetts doesn’t have reciprocity agreements with neighboring states, so employees working across state lines typically need to file returns in both states and you need to withhold accordingly.

State unemployment insurance rates vary significantly and depend on your experience rating in each state. You might pay 2.5% in one state and 4% in another, even for similar employees. These rates change annually based on your claims history in each state.

Remote work has made multi-state payroll much more common. An employee who used to work at your Massachusetts office but now works from their house in Connecticut means you’ve become a multi-state employer overnight. The rules around remote work and pandemic-era relocations are still being clarified by state tax authorities, which adds another layer of uncertainty.

The practical reality is that this complexity is exactly why full-service payroll makes sense for most small businesses. Modern payroll systems handle multi-state automatically once you’ve registered in each state and entered employee work locations correctly. They apply the right withholding rates, generate state-specific reports, and file quarterly returns for each state on your behalf.

Trying to manage multi-state payroll manually is a recipe for problems. Miss a registration deadline and you’re non-compliant from day one. Use the wrong withholding rate and your employee owes money at tax time. Miss a quarterly filing and penalties start accumulating before you realize something went wrong.

What you need to do: identify every state where employees actually perform work, register as an employer in each of those states, configure your payroll system to track work locations, and ensure quarterly filings happen for every state where you have workers. For businesses providing small business bookkeeping in MetroWest Massachusetts, we see this come up often when contractors hire crew members who live across state lines or when professional services firms let employees work remotely.

If you have employees traveling between states regularly, you may need to track days worked in each location. Some states have thresholds for when withholding kicks in, but the tracking burden falls on you as the employer. This is another area where having the right systems in place from the start saves significant headaches later.