Sequential location recommendation plays an important role in,many applications such as mobility prediction, route planning and,location-based advertisements. In spite of evolving from tensor,factorization to RNN-based neural networks, existing methods did,not make effective use of geographical information and suffered,from the sparsity issue. To this end, we propose a Geographyaware sequential recommender based on the Self-Attention Network (GeoSAN for short) for location recommendation. On the one,hand, we propose a new loss function based on importance sampling for optimization, to address the sparsity issue by emphasizing,the use of informative negative samples. On the other hand, to make,better use of geographical information, GeoSAN represents the hierarchical gridding of each GPS point with a self-attention based,geography encoder. Moreover, we put forward geography-aware,negative samplers to promote the informativeness of negative samples. We evaluate the proposed algorithm with three real-world,LBSN datasets, and show that GeoSAN outperforms the state-of-theart sequential location recommenders by 34.9%. The experimental,results further verify significant effectiveness of the new loss function, geography encoder, and geography-aware negative samplers.