{{Infobox river | name = Kostroma | image = Kostromka.jpg | image_size = 250 | image_alt = Kostroma near Most Sandogora | image_caption = View of the Kostroma near the village of Most Sandogora | map = Volga basin.png | map_size = 200 | map_alt = Volga basin | map_caption = Volga basin | source1_location = near Knyazhevo Chuhlomskogo | mouth_location = Gorky Reservoir at Kostroma | mouth_coordinates = {{coord|55.9283|34.5382|region:RU|display=it}} | subdivision_type1 = Country | subdivision_name1 = Russia | progression = {{RVolga}} | length = {{convert|354|km|mi|abbr=on}} | source1_elevation = | mouth_elevation = | discharge1_avg = {{convert|85|m3/s|cuft/s|abbr=on}} | basin_size = {{convert|16000|km2|mi2}} | river_system = Volga | tributaries_left = Vocha, Mezenda, Vyoksa, Tyobza, Shacha | tributaries_right = Shugoma, Svetitsa, Selma, Monza, Obnora }} The '''Kostroma''' ({{langx|ru|Кострома́}}) is a river in the European part of Russia. It flows through the Kostroma and Yaroslavl Oblasts, and becomes a left tributary of the Volga, which it enters at the Gorky Reservoir, at the city of Kostroma.
Prior to the flooding of the Gorky Reservoir in 1955-1957, the Kostroma River flowed into the Volga within the city limits of Kostroma. The Ipatiev Monastery stands at the old confluence of the Kostroma and the Volga.
The river is {{convert|354|km|mi}} long, and its drainage basin covers {{convert|16000|km2|mi2}}.<ref name=gvr>[https://textual.ru/gvr/index.php?card=175932 «Река Кострома»], Russian State Water Registry</ref> The average water flow is {{convert|71|m3/s|cuft/s}} at the town of Buy, {{convert|124|km}} from the mouth,<ref>[https://bse.sci-lib.com/article065253.html ''Kostroma (river in Kostroma reg.)'' article from the Great Soviet Encyclopedia] {{in lang|ru}}</ref> and {{convert|85|m3/s|cuft/s}} at the mouth
Major tributaries include the Vocha, Mezenda, Vyoksa, Tyobza, and Shacha on the left, and the Shugoma, Svetitsa, Selma, Monza, and Obnora on the right.<ref name=gvr/> Before the establishment of the Gorky Reservoir, the Sot and Mesa were also tributaries; they now flow directly into the reservoir.
The towns of Soligalich and Buy stand on the river.
The Kostroma freezes up in November and thaws in April or early May.
The Kostroma begins near the village of Knyazhevo Chuhlomskogo in the Kostroma Oblast. The upper river is relatively narrow and winding, but it soon gathers the water of many tributaries, increasing its width to about {{convert|30|m}} or {{convert|40|m}}.{{citation needed|date=July 2020}} In the upper and middle reaches of the riverbed there are rapids, and the banks are often wooded and sometimes steep. Here it is suitable for swimming due to the large amount of snags and debris.
By the time it flows past the town of Buy, the width of the river exceeds {{convert|60|m|ft|sp=us}}; from this point on the river is navigable. From here down to the reservoir it begins to form large bends and oxbow lakes, and sometimes floods.
The last {{convert|50|km}} of the Kostroma's course form the border between the Yaroslavl and Kostroma oblasts.
== Etymology == {{Commons category|Kostroma River}}The river bears the name of the Slavic goddess Kostroma.
==References== {{reflist}}
{{Volga River}} {{Rivers of Russia}}
<!--Categories--> Category:Rivers of Kostroma Oblast Category:Rivers of Yaroslavl Oblast