Rapid ascent to High Altitude (HA) can cause severe damage to body organs and may lead to many fatal disorders. During induction to HA, human body undergoes various physiological, biochemical, hematological and molecular changes to adapt to the extreme environmental conditions. Many literature references hint that gene-expression-regulation and regulatory molecules like microRNAs (miRNAs) and Transcription Factors (TFs) control adaptive responses during HA-stress. These biomolecules are known to interact in a complex combinatorial manner to fine-tune the gene expression and help in controlling the molecular responses during this stress and ultimately help in acclimatization. HAHmiR.DB (High-Altitude Human miRNA Database) is a unique, comprehensive, curated collection of miRNAs that have been experimentally validated to be associated with HA-stress; their level of expression in different altitudes, fold change, experiment duration, biomarker association, disease and drug association, tissue-specific expression level, Gene Ontology (GO) and Kyoto Encyclopaedia of Gene and Genomes (KEGG) pathway associations. As a server platform it also uniquely constructs and analyses interactive miRNA-TF-Gene coregulatory networks and extracts regulatory-circuits/Feed Forward Loops (FFLs) using in-house scripts. These regulatory circuits help to offer mechanistic insights in complex regulatory mechanisms during HA stress. The server can also build these regulatory networks between two and more miRNAs of the database and also identify the regulatory-circuits from this network. Hence HAHmiR.DB is the first-of its-kind database in HA research which a reliable platform to explore, compare, analyse and retrieve miRNAs associated with HA stress, their coregulatory networks and FFL regulatory circuits. HAHmiR.DB is freely accessible at http://www.hahmirdb.in