Which brand of cigarettes has the highest nicotine and tar content?

In 1998, Newport 100s and unfiltered Camels were tied for highest nicotine yield at 2.9 milligrams. In 2004, Newport had risen to 3.2 milligrams, and five brands measured 3 milligrams or higher.

http://www.washingtonpost.com/wp-dyn/content/article/2006/08/30/AR2006083001418_pf.html

Internationally, there are significantly higher results than for US brands. This link has a table of results for New Zealand cigarettes with a number of brands over 3 mg. The highest is Port Royal Regular 50g at 4.12 mg of nicotine. (Somewhat dated, but the links on previous responses indicate that the content seems to be increasing, so these 1997 values may even be lower than current ones!)

[From globalink.org 2009 article, no longer online]

Here is an FTC document with tar, nicotine, and carbon monoxide numbers for the years 1998 through 2005:

https://www.ftc.gov/sites/default/files/documents/reports/2000-report-tar-nicotine-and-carbon-monoxide-covering-1998/1998tarnicotinereport_0.pdf

https://www.erowid.org/plants/tobacco/tobacco_nic.shtml (A-Z list)

Also, the tar and nicotine numbers for cigarettes manufactured by Philip Morris can currently be found on their website and the numbers for some brands manufactured by R.J. Reynolds can be found on the brands' official websites.