1099 Contractor in Washington with a Illinois Client: Where Do You File?
Answer
Washington taxes nothing, and Illinois taxes you only if you work there. Living in Washington means no resident return at all. A Illinois client does not create a Illinois filing obligation by itself — physically performing services inside Illinois does, and then only for that portion.
Last verified
The most common contractor worry — that invoicing an out-of-state client creates a filing obligation there — is usually unfounded. What creates the obligation is physical presence, and Washington residents have no home-state return in any case.
Illinois allows a 30-day safe harbour before the obligation attaches. Illinois does not require an employer to withhold from a nonresident who works in Illinois for 30 or fewer days in the year. The day count is a withholding safe harbour; a nonresident who exceeds it owes Illinois tax on the Illinois-source wages.
What you file
- 1Nonresident return · IllinoisForm IL-1040 with Schedule NR
File a Illinois nonresident return only for income from services you physically performed in Illinois. Washington does not tax wage or self-employment income.
The two states, side by side
| Washington | Illinois | |
|---|---|---|
| Taxes wages | No | Yes — flat |
| Reciprocity partners | None | 4 (Form IL-W-5-NR) |
| Convenience rule | No | No |
| Nonresident return | Not applicable | Form IL-1040 with Schedule NR |
| Credit for other-state tax | No income tax | Schedule CR |
| Nonresident safe harbour | Not applicable | 30 days |
| Local income tax | No | No |
| Revenue department | Washington State Department of Revenue | Illinois Department of Revenue |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Illinois and working in Washington gives:Home state only — estimated payments.
Same two states, different situation
The withholding answer turns on how you are paid and where the work happens, not only on which two states are involved.
- W-2 commuter: Washington → IllinoisWork state only
- Remote worker: Washington → IllinoisNo state income tax on your wages
- Moved mid-year: Washington → IllinoisOne part-year return — the state you moved to
Other Washington pairs
Questions people actually ask
I live in Washington and my client is in Illinois. Do I have to file a Illinois tax return?
Washington taxes nothing, and Illinois taxes you only if you work there. Living in Washington means no resident return at all. A Illinois client does not create a Illinois filing obligation by itself — physically performing services inside Illinois does, and then only for that portion.
Do reciprocity agreements help a 1099 contractor?
No. Every state reciprocity agreement in the country is an arrangement about wage withholding between two revenue departments, and a 1099 has no withholding to switch off. Whether Washington and Illinois hold an agreement makes no difference to a self-employed filer — sourcing rules decide the answer instead.
How current is this?
The Washington and Illinois rules on this page were last checked against Washington State Department of Revenue and Illinois Department of Revenue on 2026-08-07. We re-check the full grid every December after state legislative sessions close, and re-check the convenience-of-the-employer states quarterly because that is where the rules move fastest.
Sources
Every fact above comes from the revenue department that publishes the rule. We do not cite secondary summaries, and we do not restate a figure we could not find at source.
- Washington State Department of Revenue — individual income taxaccessed 2026-08-07
- Illinois Department of Revenue — individual income taxaccessed 2026-08-07