The DPRK may or may not have nukes, it has been suggested that they have, and suggested more recently that they haven't. One thing is for sure, they have the capabilities and resources to make nuclear weapons. They have several reactors that can refine plutonium to be used in nuclear weapons, I can list the details if anyone wants.
In terms of missiles they certainly can reach the U.S.
The missile with the longest range is the the Taepo Dong-2 ICBM, it has a maximum range of 6,200 miles. The US DIA (Defense Intelligence Agency) estimates that the missile has a range of about 4,650 miles with large nuclear warheads and 6,200 miles with smaller warheads. At the extreme of 6,200 mil es, the missile could reach all major West Coast cities (Los Angeles, San Francisco, San Diego,,,) and reach as far east as Chicago.
The DPRK are not going to such weapons (if they have them) unless provoked, that is my belief anyhow.
Formerly known as Chairman Mao
Between the people and their enemies there can be nothing in common but the sword; we must govern by iron those who cannot be governed by justice
~Saint-Just
I condemn the dust of which I am made, this dust that speaks to you now. It can be persecuted, it can be brought to death. But I challenge the world to take from me that part of me which will live through the centuries and survive in the skies.
~Saint-Just