Using　novel　Internet　search　data　from　Baidu　Index,　this　study　examines　for　the　first　time　the　nationwide　distribution　of　city-level　intensity　of　online　suicidal　ideation　in　China　and　the　underlying　social　determinants　and　processes.　We　find　that　the　intensity　of　suicidal　ideation　shows　moderate　spatial　clustering,　decreasing　from　east　to　west　nationally　and　from　developed　to　less　developed　areas　within　each　province.　Overall,　socioeconomic　inequality,　social　fragmentation　as　represented　by　single-generation　households　and　religiosity,　and　the　proportion　of　older　adults　are　positively　associated　with　suicidal　ideation.　Social　deprivation,　divorce　rate,　and　male-to-female　sex　ratio　have　significant　negative　effects　on　suicidal　ideation,　while　marriage　rate　has　insignificant　effects.　Further　analyses　based　on　geographically　weighted　regression　suggest　that　the　direction,　magnitude,　and　statistical　significance　of　the　set　of　risk　factors　relevant　to　suicidal　ideation　vary　by　contexts　and　that　city-specific　interventions　for　suicide　prevention　are　needed.