Erythropoiesis is regulated at multiple levels to ensure the proper generation of mature red cells under multiple physiological conditions. To probe the contribution of long non-coding RNAs (lncRNAs) to this process, we examined >1 billion RNA-Seq reads of polyadenylated and non-polyadenylated RNA from differentiating mouse fetal liver red blood cells, and identified 655 lncRNA genes including not only intergenic, antisense and intronic but also pseudogene and enhancer loci. Over 100 of these genes are previously unrecognized and highly erythroid-specific. By integrating genome-wide surveys of chromatin states, transcription factor occupancy, and tissue expression patterns, we identify multiple lncRNAs that are dynamically expressed during erythropoiesis, show epigenetic regulation and are targeted by key erythroid transcription factors GATA1, TAL1 or KLF1. We focus on 12 such candidates and find that they are nuclear-localized and exhibit complex developmental expression patterns. Depleting them severely impaired erythrocyte maturation, inhibiting cell size reduction and subsequent enucleation. One of them, alncRNA-EC7, is transcribed from an enhancer and is specifically needed for activation of the neighboring gene encoding BAND3. Our study provides an annotated catalog of erythroid lncRNAs, readily available through an online resource, and shows that diverse types of lncRNAs participate in the regulatory circuitry underlying erythropoiesis.