A race is on this page if it is run in Ohio and includes a 5K — whether as a standalone race or as one distance inside a larger weekend. Where a weekend also carries a 10K, a half or a marathon, that is noted, because it changes what the published participation number means.

The rule for every cell below: a date or a figure needs a named source and the year it belongs to. Where the only source is a third-party listing site rather than the organiser, the row says check. Nothing on this page is estimated, and an empty cell stays empty.

Every dated note in the vault tagged or categorised running shows up here. Adding a race as a dated event note — see the checklist at the foot of the page — puts it on this calendar and into the site's feed automatically.

Most of these races hold a weekend rather than a date, which is what makes them predictable. This is the recurring rule for each, with the dates confirmed so far.

Everything outside these weekends is the long tail — the club races, park districts, school fundraisers and township trots that make up most of the Ohio 5K calendar and none of the headlines. They are not on this page yet.

So the Year totals table means the same thing every time it is filled:

1. Pick one calendar as the spine and name it in the Counted from column. The statewide listings worth using are RunSignup, RunGuides, Running in the USA and OhioRuns.
2. Filter to the state of Ohio and to the 5K distance only. A weekend that offers a 5K among other distances counts once.
3. Count events, not race days — a two-day weekend with one 5K is one event.
4. Exclude virtual-only entries and anything with no date set.
5. Record the date counted. These calendars keep adding races through the year, so a January count and a September count of the same year are different numbers and are only comparable to counts taken in the same month.
6. For field sizes, prefer in order: the organiser's own post-race release, then named local coverage, then a results page's finisher count on Athlinks or RunSignup. A listing site's "size band" is a last resort and should be labelled as one.

• The 5th Line 5K — overview — 2027 date, field, Nationwide Arena finish
• Arnold 5K, Pump & Run and Ruck see record growth — M3S Sports
• 43rd Heart Mini-Marathon and Walk — distances and registrant count
• Heart Mini-Marathon, Walk raises nearly $3 million — FOX19, 2026 edition
• OhioHealth Capital City Half Marathon returns to Columbus April 25 — ABC6
• Records Fall at 28th Annual Flying Pig Marathon — 5K and weekend figures, 2026 dates
• 2026 Cleveland Marathon guide — 5K and 10K on Saturday 16 May, 7:30 a.m.; clevelandmarathon.com for the 2027 weekend
• 2026 Susan G. Komen Columbus Race for the Cure — date, time, North Bank Park
• The Gathering Place Race for the Place 2026
• Grandview Yard Half & Quarter Marathon sets record in fourth year — M3S Sports
• Komen Northeast Ohio Race for the Cure — race information — third-party listing, date unconfirmed
• Wright State hosts thousands for the Air Force Marathon 5K · 2025 Air Force Marathon drew more than 7,600
• Columbus SKECHERS Hot Chocolate Run — 15 Nov 2026, 5K at 7:30 a.m., McFerson Commons
• Thanksgiving 5K a beloved holiday tradition in Licking County — Granville Turkey Trot
• Tuscarawas County YMCA Turkey Trot raises record amount
• 2025 Western & Southern Thanksgiving Day Race
• Dayton Turkey Trot Half Marathon & 5K — third-party listing, date unconfirmed