We present experimental evidence for the ion-cyclotron resonant-heating (ICRH) induced trapping of ions in the edge-mirror fields of a magnetically confined plasma. Relative changes in edge-plasma density have been monitored in an end cell of the Phaedrus-B Tandem Mirror (Breun R A et al 1981 Phys. Rev. Lett. 47 1833 - 6; Ferron J R et al 1983 Phys. Rev. Lett. 51 1955) via the use of electron cyclotron emission from a hot-edge population created by the application of electron cyclotron resonant heating. Edge-plasma density dependence upon the ICRH left-circularly-polarized electric field and on the edge-neutral density were found to be consistent with an edge rf-trapping model. A linear correlation is observed between the change in trapped edge density and the change in the applied ICRH . Furthermore, it is demonstrated that cold (less than 7 eV) ions born from atomic processes operating at or near the plasma edge are the dominant species participating in the trapping process. The results obtained are shown to be applicable to any device with mirror-like closed particle orbits at the plasma edge.