I have a question! How is big the nazism and anti-semitism etc in USA? I don't know the situation there...
But I have heard, there is a nazi party, called NSM?
I know plenty of Nazism in the US, obviously because we have 302 million people, the higher population means we are going to have more Nazi groups.
The most well known/popular groups are KKK (Ku Klux Klan), National Socialist Movement, and the Aryan Brotherhood.
Neither are much a threat because of their decline, the KKK is in a huge decline and is reduced to a militia movement in rural areas mainly, they are no where near what they were years ago. NSM is not taken seriously, Aryan Brotherhood is primarily a prison gang and most Nazis would call them race traitors.
There are other movements that are serious threats but perhaps not as well known
National Alliance by Dr William Pierce. This is the organization responsible for publishing the Turner Diaries and they generally hijack movements that are conservative to recruit members blaming Jews on illegal immigration and gun control, etc.
National Vanguard, similar to NA
StørmFrønt (not really a organization but a meeting point for white nationalists)
Blood & Honour/Combat 18 based out of Florida and the UK, they are a more militant group mainly skinheads
WAR (White Aryan Resistance) Tom Metzger group mainly radio show, not sure their current status.
overall, it depends on your area. I live in a rural area of Florida and there are some KKK but it's not very common.
Most of the Neo Nazis are in the midwest or California.
I hate to link to the ADL because I despise the ADL but it references to most of the nazi groups in the US. Some of the groups listed aren't even Nazi groups.
http://www.adl.org/learn/ext_us/american_front/default.asp?LEARN_Cat=Extremism&LEARN_SubCat=Extremism_in_America&xpicked=3&item=american_frontTheir movement section lists group that aren't necessarily nazis either
http://www.adl.org/learn/ext_us/Christian_Identity.asp?LEARN_Cat=Extremism&LEARN_SubCat=Extremism_in_America&xpicked=4&item=Christian_ID