National accreditation is conferred on vocational, "career" and technical schools. Most of them are for-profits. Even if the offer degrees they are still, well, vocational, "career" and technical schools, let's say VCTs. They are over 50 national accrediting agencies which accredit such varied schools as landscape design, denture making, medical assistant and so on. Some of these agencies also accredit supposed academic schools, such as well Crown College. However, generally regionally accredited schools will not accept credits from nationally accredited schools. Here is an article that does a good job of summarizing regional vs. National Accreditation which is taken from the Education USA website.
You should also be aware that many U.S. institutions that hold regional accreditation do not recognize credits or degrees earned at other U.S. institutions that are nationally accredited. This will be important to you if you decide to transfer from one U.S. institution to another part way through a degree program, or if you plan to pursue degrees at different U.S. institutions; for example, a bachelor’s degree from one school and a master’s degree from another.
Another article on accreditation from Elearners.com:
Issues to Consider
When deciding which type of accreditation is right for you, there are several issues you may wish to consider.
The main issue is the transferability of credits from one institution to another. While nationally accredited institutions will usually accept credit from regionally or nationally accredited institutions, regionally accredited schools often do not accept credit from nationally accredited institutions.
This also means that if you hold an Associate's degree from a nationally accredited school, you may have to start over if you later decide to pursue a Bachelor's degree from a regionally accredited school. Similarly, if you hold a nationally accredited Bachelor's degree, you may not be eligible to enter a Master's program at some regionally accredited institutions. Considering that state colleges and universities are regionally accredited, and are an inexpensive local option for many students, this is definitely something to keep in mind.
Many regionals refuse to accept nationals' credits for transfer is because they claim they are inferior and they are. Regional accreditation is much more academically oriented and stringent. Nationals' accrediting standards are not as strict and they are more oriented to preparing people for careers or vocations, not providing a "well rounded education." Of course, nationals say that is not true and the fact that their accreditors are recognized by the Department of Education shows they are the equivalent. The Department of Education does not run any schools or even accrediting agencies! It simply decides what minimum requirements an accrediting agency must meet. Now of course national accredited schools will make a lot of supercilious arguments since they have a conflict of interest! It has something to do with .... the bottom line and it is hurt by the fact that the education is perceived as inferior when their credits don't transfer AND less students are going to be inclined to attend their schools if they can't transfer. Look at Crown College, when they were ordered to distribute a paper to each of their students explaining that their credits don't transfer, they just ignored it. It was better to risk the court's wrath that potentially lose students.