Federal Controlled Substances Act (Title 21 Chapter 13 of the United States Code:  Drug Abuse Prevention and Control)
The United States’ Controlled Substances Act (CSA) prohibits unauthorized manufacturing, distributing or dispensing of controlled substances as well as their possession for the purpose of distributing or dispensing.  The law also addresses the distribution of profits made through the drug trade and the impact violating the Act has on eligibility for Federal benefits of various kinds (grants, loans, contracts, and forms of assistance, such as Social Security assistance to families  or food stamps).  Special prohibitions (and penalties) against distributing drugs to minors or using minors to distribute drugs, as well as prohibitions against distributing near a school, interstate highway or truck stop, are also part of the Controlled Substances Act. 
Controlled substances are both illicit drugs or diverted licit drugs (those with a limited legal, medical usage) as well as some chemicals used to make drugs.  Federal law generally focuses on larger quantities of controlled substances than state and local laws or on interstate or international trafficking of drugs and money laundering that state laws have no jurisdiction over.  Similarly, penalties are usually much higher than those at the state or local level.  For example, a crime that might bring a year in jail at the state level might bring 10 years at the federal level, because that crime will involve much larger quantities of a controlled substance or listed chemical and will impact a larger area and more people. 
For more detailed information about the Controlled Substances Act, go to www.dea.gov/pubs/csa.html