Lake Kapowsin

{{Infobox body of water

| name = Lake Kapowsin

| native_name =

| native_name_lang =

| image = File:1 Kapowsin and Rainier.jpg

| alt =

| caption =

| pushpin_map = Washington

| pushpin_map_alt =

| pushpin_map_caption =

| image_bathymetry =

| alt_bathymetry =

| caption_bathymetry =

| location = Pierce County, Washington

| coords = {{coord|46|58|42|N|122|13|07|W|region:US-WA_type:waterbody|display=inline,title}}

| type =

| inflow = Ohop Creek

| outflow = Kapowsin Creek

| length =

| width =

| area = {{convert|512|acre|abbr=on}}

| depth = {{convert|20|-|30|ft|abbr=on}}

| max-depth = {{convert|30|ft|abbr=on}}

| volume =

| residence_time =

| elevation = {{convert|584|ft|abbr=on}}{{gnis|1521570|Lake Kapowsin}}

| cities =

• Kapowsin, Washington
• Voss Resort

| website =

| reference =

}}

Lake Kapowsin {{IPAc-en|k|ə|ˈ|p|aʊ|.|ə|.|s|ᵻ|n}} is a lake in Pierce County, Washington, about halfway between Tacoma on Puget Sound, and Mount Rainier in the Cascade Mountains. The lake is {{convert|2.5|mi}} long and {{convert|0.15|-|0.5|mi}} wide, lying in a channel formed by meltwater from the Puget lobe of the Vashon glacier during the Pleistocene glaciation. A small island, Jaybird Island, lies in the northern half of the lake.{{citation|title=7.5 minute quadrangle map "Lake Kapowsin, WA"|publisher=United States Geological Survey}} As indicated by a drowned forest in the lake and other evidence, the Puyallup River was inundated about 550 years ago by a lahar from Mount Rainier called the Electron Mudflow. The mudflow partially filled the channel (leading to its shallow, smooth bottom today) and blocked Ohop Creek's outlet, forming present-day Lake Kapowsin.{{rp|A69–A70}}

The Tacoma Rail shortline runs along the west side of the lake, as does Orville Road connecting Eatonville to the south with the town of Kapowsin.

The lake contains a number of fish species and is stocked with rainbow trout, rated "excellent" for fishing by Washington Department of Fish and Wildlife, as is the yellow perch.