State Income Tax, Nexus, and Remote Employees: What Changes When You Hire Across State Lines

Remote work made it easy to hire the best person regardless of location. It also made it easy to create compliance obligations in a new state with a single hire. The federal rules do not change. The state rules do, and they vary enough that a small business with staff in three states can end up with three payroll registrations, three sets of rules, and potentially three income tax filings.

The types of obligations

When an employee lives and works in a different state, several separate regimes can be triggered:

Payroll withholding. The state where the employee performs services generally requires the employer to withhold that state's income tax from wages, if the state has an income tax. Reciprocity agreements between some neighboring states can change this.
State unemployment insurance. Employers register and pay unemployment tax in the state where the employee's work is localized (or where the employee is based).
Other payroll programs: disability insurance, paid family leave, workforce funds, local taxes.
Workers' compensation coverage for the employee's state.
Business income tax nexus: the employer's activity, including employees and property, may create income tax or franchise tax filing obligations for the business (or the pass-through owners).
Sales tax nexus: employees can create physical nexus for sales tax. See sales tax nexus basics.
Foreign qualification: the entity may need to register to do business in the state. See foreign qualification basics.
Employment law: wage and hour, leave, and pay transparency rules of the employee's state.

Public law protections and thresholds

Federal law provides limited protection from state business income tax for sellers of tangible goods whose only activity in the state is solicitation of orders, but that protection does not cover services and does not cover employees doing more than solicitation. There is no general de minimis threshold for payroll withholding in many states from the first day or dollar of work, though some states have short-term thresholds (such as days worked in the state) for nonresident employees.

Individual income tax for owners

Owners of pass-through entities may owe nonresident income tax in states where the entity does business or earns income, and the entity may need to file composite or withholding returns on behalf of nonresident owners. An S-corp with employees in another state could generate sourced income to that state for its shareholders. Filing and paying in more than one state also requires credit for taxes paid to other states on the owner's home state return. See pass-through entity tax.

Where the owner lives matters too

State residency rules can claim taxes on all income for residents. Domicile and statutory residency rules (counting days in a state) sometimes surprise owners who split time between states. If you work in more than one state, track your days.

Hiring checklist for a new state

Before the employee starts:

Confirm where the employee will actually work and whether they may travel or move.
Research the state's requirements for withholding registration, unemployment registration, and local taxes.
Register with the state agencies and obtain account numbers.
Update your payroll system with the new state, tax rates, and employee's work location.
Check foreign qualification requirements and file if needed.
Review workers' compensation and confirm coverage extends to the state.
Review state employment laws (paid sick leave, final pay rules, meal breaks, noncompete rules).
Check for local taxes in the employee's city or county.
Document the arrangement in the employment agreement, including the work location and who pays for home office items.
Consider the effect on business income tax: a state may claim nexus when the business has employees, and apportionment of income may apply.

Temporary work and travel

Employees who travel to other states for short periods may create nonresident withholding obligations depending on thresholds by state. For example, some states require withholding from the first day, others only after a number of days. Track employee travel if you send staff into states with strict rules. Owners who travel and perform services in other states may also owe nonresident tax on that income.

Reciprocity and credits

Some neighboring states have reciprocal agreements that allow residents of one state to work in the other and pay tax only to their state of residence, with employees filing an exemption form. These agreements do not remove the need for unemployment registration or other requirements. Without a reciprocity agreement, employees may owe tax in both states and claim a credit in the resident state.

Independent contractors

Contractors in another state generally do not trigger withholding or unemployment registration if properly classified, but they can still contribute to nexus in some cases (for example, sales representatives soliciting in the state). Misclassified contractors can create the same obligations as employees. See contractor vs employee.

Digital nomad and temporary relocations

Employees who temporarily work from a vacation home or move without notifying the employer can create surprises. Have a policy requiring employees to notify you before working from another state for extended periods, and specify which states you support.

Common mistakes

Paying employees under the home state's rules when they work elsewhere.
Learning about a remote employee's move after months have passed.
Ignoring unemployment registration.
Assuming an LLC has no obligation in states where employees work.
Not tracking days for travelers.
Overlooking local taxes.
Failing to register the entity as a foreign entity.
Forgetting state workers' compensation.
Not updating estimated payments for nonresident state taxes.

Cost-benefit thinking

Sometimes the added compliance cost of a remote hire is minor compared to the talent benefit. Other times, it is significant: many registrations, more expensive payroll setup, and new tax filings. If you are hiring your first remote employee in a state, get a full picture before making an offer.

Practical tools

Use a payroll provider that supports multi-state compliance and can register with states for you. Keep a spreadsheet of states, registrations, account numbers, due dates, and responsible persons. Add the state deadlines to your calendar. See small business tax calendar.

For help identifying obligations in a new state, AE Tax Advisors can assist, and a discovery call is a good first step. Employment law questions belong with an employment attorney.