circSC employs a compendium of full-length single-cell RNA-sequencing datasets composed of 254,590 cells from 171 public studies to generate a comprehensive map of circRNAs in human and mouse cells. circSC identifies a total of 196,491 human and 310,969 mouse circRNAs in these scRNA-seq libraries, revealing the cell-type-specific expression pattern of circRNAs in brain samples, developing embryos, and breast tumors. circSC provides the uniquely expressed circRNAs in different cell types and demonstrates the promising performance of circRNAs as cell-type biomarkers.