Can you book just one night at Kirk Creek Campground?

Kirk Creek Campground, a Forest Service campground in Los Padres National Forest, sets a minimum stay of two consecutive nights, rising to three nights over holiday weekends. The maximum stay is 14 consecutive nights. Source: https://www.recreation.gov/camping/campgrounds/233116

The Los Padres National Forest's own facility page confirms the 14 day maximum stay as a standing restriction for this site, booked through Recreation.gov or by calling 1-877-444-6777. Source: https://www.fs.usda.gov/r05/lospadres/recreation/kirk-creek-campground

Based on this, a straight single night booked from scratch is not available at Kirk Creek: the reservation system applies the two night floor (three over holidays) at the point of booking, and there is no published exception that lowers it to one night for ordinary dates. Recreation.gov's general cancellation rules do allow an early departure from a longer reservation, where a customer who leaves before their scheduled checkout may request a refund for the unused nights, but this applies to shortening an existing multi-night booking rather than to reserving a single night outright. Source: https://www.recreation.gov/rules-reservation-policies

Travelers who only want one night should plan around the stated minimums rather than assume a one-night slot will be bookable: check the live availability calendar on the campground's Recreation.gov page for any already-split single-night gaps between other campers' reservations, since these can occasionally appear on the calendar even though a fresh two-night booking is the standard rule. The facility page also notes that reservations can be made as late as three days before arrival, which is useful for checking whether a last-minute single-night gap has opened up. Source: https://www.recreation.gov/camping/campgrounds/233116

In short: plan for at least two nights at Kirk Creek under normal conditions, and three nights if the stay includes a holiday weekend. There is no officially stated waiver of the minimum stay for everyday single-night requests.