BACKGROUND: Information on geographical accessibility to maternal healthcare (MHC) and coverage of maternal health service utilisation at high spatial resolution in Nepal are important for evidence-based health planning. METHODS: Based on the Nepal Health Facility Registry dataset in 2022, we measured the geographical accessibility to MHC facilities across Nepal. Using data from 2022 Nepal Demographic and Health Survey and other sources, we assessed the relationships between geographical accessibility and the utilisation of the three major healthcare services (ie, four or more antenatal care (ANC) visits, institutional delivery and postnatal care (PNC) check-up), by applying Bayesian geostatistical models. High-resolution maps on coverage of the above services were produced. RESULTS: The geographical accessibility showed high in the central and southern Terai belt but low in the northern mountains, with average travel-mode adjusted travel time for ANC, institutional delivery and PNC 26.74, 40.72 and 29.09 min, respectively. Negative correlations were found between geographical accessibility with four or more ANC visits (OR 0.76, 95% Bayesian credible interval, BCI 0.65 to 0.90), institutional delivery (OR 0.76, 95% BCI 0.64 to 0.90) and PNC check-up (OR 0.87, 95% BCI 0.76 to 0.99), respectively. Population-weighted coverages for four or more ANC visits, institutional delivery and PNC check-up were estimated 83.25% (95% BCI 80.43% to 85.35%), 84.26% (95% BCI 81.30% to 86.08%) and 73.19% (95% BCI 69.43% to 76.09%), respectively, across Nepal. The northern mountains and southeastern Terai showed low coverage for the three healthcare services, while the central, eastern and western hilly regions exhibited good coverage. CONCLUSION: Geographical accessibility is important in utilisation of maternal health services in Nepal. The high-resolution maps enable an evidence-based assessment for better health planning.