How Crowded Is Antietam National Battlefield in September?

September runs about 1.2× Antietam National Battlefield's average month, which makes it a busy month here — roughly 10% of the park's yearly visitors come in September.

In a typical September the park sees about 23,000 recreation visits, based on National Park Service monthly counts from 1979 to 2025.

That makes September the 6th-busiest of the park's twelve months, sitting between the July peak (2×) and the January low (0.2×).

On our Best Time to Visit score September rates 62/100 ("Good") — the single best-rated month at Antietam, balancing crowds against weather and daylight.

Typical September weather, from 1991–2020 NOAA climate normals at the nearest station, averages a daytime high near 78°F and an overnight low around 54°F, with about 4.4" of precipitation.

That average of about 66°F is a comfortable range for hiking and being outdoors all day.

Because June, July and August together draw about 39% of annual visitors, choosing September instead steps outside that summer crush — the single biggest lever on how crowded the park feels.

You'll have about 12.2 hours of daylight in September to explore — between the 9.2-hour midwinter low and the 14.8-hour summer high.

Park-wide, 2024 drew 197,340 recreation visits, up 28.5% from 153,560 in 2023.

Across the past decade overall visitation has eased about 60.5%, so September may feel a touch quieter than it once did.