Single-domain antibodies (SAbs) against three Yersinia pestis surface proteins (LcrV, YscF, and F1), nucleic acid sequences encoding the SAbs, and polypeptides comprising two or more SAbs capable of recognizing two or more epitopes and/or antigens. The present invention further includes methods for preventing or treating Y. pestis infections in a patient; methods for detecting and/or diagnosing Y. pestis infections; and devices and methods for identifying and/or detecting Y. pestis on a surface and/or in an environment.