A gamma-ray burst at a redshift of z approximately 8.2.

We thank Ph. Yock, B. Allen, P. Kubanek, M. Jelinek and S. Guziy for their assistance with the BOOTES-3 YA telescope observations (Supplementary Information). This work was partly based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the US National Science Foundation on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), the Ministério da Ciência e Tecnologia (Brazil) and SECYT (Argentina). This work was also partly based on observations made using ESO telescopes at the La Silla or Paranal observatories by G. Carraro, L. Schmidtobreick, G. Marconi, J. Smoker, V. Ivanov, E. Mason and M. Huertas-Company. The UKIRT is operated by the Joint Astronomy Centre on behalf of the UK Science and Technology Facilities Council. R.J.F. acknowledges a Clay Fellowship.