We used data collected from a small but increasing population of bog turtles to evaluate the surveying methods for detecting such a small population and the level of trapping effort required to reliably detect it. Trapping with unbaited traps detected this small population more reliably and with less investigator-time investment than did widely used visual and manual search techniques. This population was most easily detected in May and June, but we still needed more than 9000 trap-hours of trapping effort to reach a 95% likelihood of capturing one of the turtles present. Based on our results, we suggest a standard of 20 traps per hectare for 20 days (a 20–20 rule) as an effort level that has a very high likelihood of detecting such small but potentially viable populations.