There likely isn't a well-known lake named Lake Sarah within Las Vegas itself. Las Vegas is located in a desert and doesn't have natural lakes. There are man-made lakes used for resorts or water features, but these wouldn't be called Lake Sarah.
However, there are a couple of possibilities:
Misremembered Name: Perhaps you're thinking of another lake's name or a different location altogether. There are lakes outside of Las Vegas, for example, Lake Mead, a popular recreation area.
Man-made Feature: It's also possible you're referring to a smaller, man-made lake within a Las Vegas resort property. Some high-end resorts incorporate lakes or lagoons for aesthetics and activities like kayaking or paddleboarding. If you have any details about the location of the lake (near a specific hotel or casino), I might be able to help you identify it.
Would you like some information on other bodies of water near Las Vegas, or perhaps some ideas for outdoor activities in the area?