The nixos.org website is a bit sparse on the Nix project's history, and same with wikipedia (though separately mentions that NixOS was a research project started by Eelco Dolstra in 2003).
http://nixos.org/~eelco/pubs/phd-thesis.pdf
He also wrote this InfoQ article on the subject of Nix and NixOS which may have some useful information (2014):
https://www.infoq.com/articles/configuration-management-with...
The Wikipedia pages for Nix and NixOS also have some interesting references.
https://en.wikipedia.org/wiki/NixOS
https://en.wikipedia.org/wiki/Nix_package_manager
Edit: I have been playing with NixOS at home for a few months and I think it's very interesting, but I'm a bit surprised I haven't heard more about it over the past decade or so. I'm thinking that the recent industry focus on deployments and provisioning has caused more people to come across it.
* 2007 NixOS Linux distribution
* 2009 Hydra Continuous Integration
* 2011 NixOps Cloud deployer
* 2013 First stable NixOS branch
(from http://wmertens.github.io/nixos-cfgmgmtcamp-slides/#/1/1 - non-authorative source :))
- There is a version history in the release notes appendix of the manual. [0]
- As others have posted here, the project is currently hosted on github [1], though it was originally in a svn repo. [0]
- Eelco Dolstra is the active project maintainer. [2]
- First checkin for Nix was ~March 12, 2003 (in the file nix.c/nix.cc). [1]
- Version 1.0 release on May 11, 2012 (also first release from github). [0]
[0] Release Notes: http://nixos.org/nix/manual/#sec-relnotes
[1] https://github.com/NixOS/nix
[2] https://github.com/edolstra
Edit: Thanks to sibling posts for the other info they were able to dig up for us.