Notable concerns
- Brown recluse (southern half)
- Northern/Southern black widow (rare)
Medically significant species in Ohio
| Species | Scientific | Significance | Range note |
|---|---|---|---|
| Brown Recluse | Loxosceles reclusa | Medically significant | Verified by Vetter (2008) county-level specimen review. Reports outside this range are almost always misidentifications; an estimated 80% of submitted 'brown recluses' from non-range states are other species. |
| Southern Black Widow | Latrodectus mactans | Medically significant | Southeastern United States, from southern New York to Florida, west through Texas and into |
| Yellow Sac Spider | Cheiracanthium inclusum | Moderate | Throughout the continental United States and southern Canada. |
| Northern Black Widow | Latrodectus variolus | Medically significant | Eastern North America from southern Canada through New England and the Appalachian region |
All documented species in this index
Species below are present in Ohio according to extension publications and the rangeStates records in our species index. Click through for full profiles.
- Brown Recluse - Loxosceles reclusa (Medically significant)
- Southern Black Widow - Latrodectus mactans (Medically significant)
- Yellow Sac Spider - Cheiracanthium inclusum (Moderate)
- Northern Black Widow - Latrodectus variolus (Medically significant)
- Common House Spider - Parasteatoda tepidariorum (Low)
- Wolf Spider - Lycosidae (family overview) (Low)
- Cellar Spider - Pholcus phalangioides (Not medically significant)
- Bold Jumping Spider - Phidippus audax (Low)
- Yellow Garden Spider - Argiope aurantia (Not medically significant)
- Grass Spider - Agelenopsis spp. (Not medically significant)
Seasonal activity in Ohio
Spider activity in Ohio follows the documented peak season of May–September. Indoor sightings often spike in late summer and early fall as males wander to find mates and as cooling outdoor temperatures push synanthropic species toward heated structures.
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Highlighted months reflect the state extension peak-activity window. Individual species (especially indoor recluse populations) may be active outside this range.
Prevention checklist for Ohio homes
- Seal exterior gaps wider than 1/8 inch around utility penetrations, dryer vents, and weep holes. Install door sweeps on garage and basement entries.
- Reduce harborage by storing firewood, lumber, and seldom-used boxes off the ground and at least 18 inches from foundation walls.
- In recluse-active areas, inspect stored clothing, bedding, and shoes before use. Sticky monitor traps placed along baseboards quantify indoor density.
- For widow-active areas, wear gloves when handling outdoor electrical boxes, irrigation valves, and stacked materials. Widows favor undisturbed voids.
- Vacuum webs, egg sacs, and spiders rather than spraying. Mechanical removal outperforms most over-the-counter residual sprays for synanthropic species.
If you are bitten
Nearby states in the Midwest region
- Spiders of Illinois - peak activity may–october
- Spiders of Indiana - peak activity may–october
- Spiders of Iowa - peak activity may–september
- Spiders of Michigan - peak activity may–september
- Spiders of Minnesota - peak activity june–august
- Spiders of Missouri - peak activity april–october
- Spiders of Wisconsin - peak activity may–september
Sources
- [1]OSU spider identification - OSU Cooperative Extension. Accessed 2026-06-14.
- [2]Spiders and scorpions submitted as suspected brown recluse - Vetter RS, 2008. Accessed 2026-06-14.