克莱德湾位于苏格兰西南，是不列颠群岛最大和最深的海湾，西侧的琴泰半岛将之与大西洋隔开，东至艾尔郡。基尔布兰南海峡是克莱德湾的一部分，将琴泰半岛与阿伦岛隔开。克莱德湾的气候受到美洲墨西哥湾暖流的影响。

克莱德湾入口的宽度为26英里（42千米）。它在北部地区与隆湖和盖尔湖连接，格里诺克便坐落于这一区域内，克莱德河由此注入湾内。

克莱德河与克莱德湾的文化和地理分界较为模糊。苏格兰人有时称邓巴顿“坐落于克莱德湾上”，而格拉斯哥港和格里诺克的居民常将北部的湾区直接称为“河”。

The Firth of Clyde encloses the largest and deepest coastal waters in the British Isles, sheltered from the Atlantic Ocean by the Kintyre peninsula which encloses the outer firth in Argyll and Ayrshire, Scotland. The Kilbrannan Sound is a large arm of the Firth of Clyde, separating the Kintyre Peninsula from the Isle of Arran. Within the Firth of Clyde is another major island - the Isle of Bute. Given its strategic location, at the entrance to the middle/upper Clyde, Bute played a vitally important military (naval) role during World War II.