1099 Contractor in Illinois with a Delaware Client: Where Do You File?
Answer
Illinois always, Delaware sometimes. With no withholding on a 1099 the whole tax is yours to manage: estimate to Illinois through the year, and file a Delaware nonresident return for any income from work you physically performed in Delaware, claiming the credit back on the Illinois return.
Last verified
The client's location is the wrong thing to track. What matters is where you were sitting when you did the work — which is why a contractor's exposure to Delaware is measured in days on the ground rather than in invoices sent.
Delaware publishes no de minimis day count or dollar floor for nonresidents. Any Delaware-source wage income above the state's general filing threshold requires a nonresident return, and that threshold is reset each year — check the current figure on the Delaware Division of Revenue nonresident instructions before filing.
What you file
- 1Quarterly estimated payments · Illinois
Make quarterly estimated payments to Illinois Department of Revenue on your full self-employment income — nothing is withheld from a 1099.
- 2Nonresident return · DelawareForm PIT-NON
File a Delaware nonresident return only if you performed services inside Delaware. Delaware publishes no de minimis day count or dollar floor for nonresidents. Any Delaware-source wage income above the state's general filing threshold requires a nonresident return, and that threshold is reset each year — check the current figure on the Delaware Division of Revenue nonresident instructions before filing.
- 3Resident return · IllinoisSchedule CR
File the Illinois resident return last and claim the credit for any tax paid to Delaware.
The two states, side by side
| Illinois | Delaware | |
|---|---|---|
| Taxes wages | Yes — flat | Yes — graduated |
| Reciprocity partners | 4 (Form IL-W-5-NR) | None |
| Convenience rule | No | Yes — general rule |
| Nonresident return | Form IL-1040 with Schedule NR | Form PIT-NON |
| Credit for other-state tax | Schedule CR | Schedule I (Form PIT-RES) |
| Nonresident safe harbour | 30 days | None published |
| Local income tax | No | Yes |
| Revenue department | Illinois Department of Revenue | Delaware Division of Revenue |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Delaware and working in Illinois gives:Home state, plus the client state if you work there.
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: Illinois → DelawareBoth states — credit offsets the double tax
- Remote worker: Illinois → DelawareConvenience-of-the-employer rule — both states tax you
- Moved mid-year: Illinois → DelawareTwo part-year returns
Other Illinois pairs
Questions people actually ask
I live in Illinois and my client is in Delaware. Do I have to file a Delaware tax return?
Illinois always, Delaware sometimes. With no withholding on a 1099 the whole tax is yours to manage: estimate to Illinois through the year, and file a Delaware nonresident return for any income from work you physically performed in Delaware, claiming the credit back on the Illinois return.
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 Illinois and Delaware hold an agreement makes no difference to a self-employed filer — sourcing rules decide the answer instead.
How current is this?
The Illinois and Delaware rules on this page were last checked against Illinois Department of Revenue and Delaware Division 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.
- Illinois Department of Revenue — individual income taxaccessed 2026-08-07
- Delaware Division of Revenue — individual income taxaccessed 2026-08-07