We compute the number of trilepton events to be expected at Fermilab as a result of the reaction pp\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}${\mathrm{\ensuremath{\chi}}}_{1}^{\ifmmode\pm\else\textpm\fi{}}$${\mathrm{\ensuremath{\chi}}}_{2}^{0}$X, where ${\mathrm{\ensuremath{\chi}}}_{1}^{\ifmmode\pm\else\textpm\fi{}}$ is the lightest chargino and ${\mathrm{\ensuremath{\chi}}}_{2}^{0}$ is the next-to-lightest neutralino. This signal is expected to have very little background and is the best prospect for supersymmetry detection at Fermilab if the gluino and squarks are beyond reach. We evaluate our expressions for all points in the allowed parameter space of two basic supergravity models: (i) the minimal SU(5) supergravity model including the severe constraints from proton decay and a not too young universe and (ii) a recently proposed no-scale flipped SU(5) supergravity model. We study the plausible experimental scenarios and conclude that a large portion of the parameter spaces of these models could be explored with 100 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ of integrated luminosity. In the minimal SU(5) supergravity model chargino masses as high as 100 GeV could be probed. In the no-scale flipped model it should be possible to probe some regions of parameter space with ${\mathit{m}}_{\mathrm{\ensuremath{\chi}}1}^{\ifmmode\pm\else\textpm\fi{}}$\ensuremath{\lesssim}175 GeV, therefore, possibly exceeding the reach of the CERN LEP II for chargino and neutralino (since ${\mathit{m}}_{\mathrm{\ensuremath{\chi}}2}^{0}$\ensuremath{\approxeq}${\mathit{m}}_{\mathrm{\ensuremath{\chi}}1}^{\ifmmode\pm\else\textpm\fi{}}$) masses. In both models such probes would indirectly explore gluino masses much beyond the reach of Fermilab.