Big room trance is a Trance subgenre that emerged in the late 2000s, evolving mostly from Tech Trance and Electro House-influenced trance, as well as Uplifting Trance and Hard Trance to a lesser degree. It is characterized by dirty, distorted leads influenced by Dutch House and Hardstyle, and many production traits associated with Big Room House, such as heavily sidechained, reverberated sound and "pryda snares". It usually keeps the bassline and hi-hat patterns typical to trance (unlike big room house, where the long-tailed kick is often the only element of low-end and percussion), and has a tempo in the 128-136 BPM range.
W&W are regarded as pioneers of the genre, followed by Ummet Ozcan, Ørjan Nilsen, Mark Sixma and many other artists releasing on Reset Records, Armada Captivating, and, especially later, Armind. Despite some of them moving towards the more popular big room house, the trance sub-genre grew in popularity in the mid-2010s as well with the help of prominent artists including Armin van Buuren, Andrew Rayel, and MaRLo. The Late 2010s brought a breath of fresh air into the genre, with the new side-project NWYR, and formation of labels inHarmony Music and Reaching Altitude Records which promoted new artists including Avao, Matrick, and Rub!k. In this period big room trance started to occasionally take some influences from Psytrance, contributing to the establishment of the trend of more commercialized psytrance.