This package provides a fast reimplementation of several density-based algorithms of the DBSCAN family. It includes the clustering algorithms DBSCAN (density-based spatial clustering of applications with noise) and hierarchical DBSCAN (HDBSCAN), the ordering algorithm ordering points to identify the clustering structure (OPTICS), shared nearest neighbor clustering, and the outlier detection algorithms local outlier factor (LOF) and global-local outlier score from hierarchies (GLOSH). The implementations use the kd-tree data structure for faster k-nearest neighbor search. An R interface to fast kNN and fixed-radius NN search is also provided.