Once you are ready to apply for your visa, visit the Russian embassy website to do so. It's important that you apply for the appropriate visa and that you are exacting with your information. Correcting misinformation is difficult, so it is better to get it right the first time. There are several different types of Russian visas, depending on the reason for your visit, so be sure to apply for the right one. Once you've done so and received your visa in the mail, review it for accuracy. Check that your name, citizenship and passport number are correct. Also, make sure that your visa validity dates coincide with your dates of travel. If you attempt to travel on dates that do not fall between your earliest and latest travel dates, you will find yourself unable to do so. Russian laws are strict in this regard. Also, be sure that the sponsor you indicated on your application is actually the person, organization or entity you intend to visit. Omission in this regard can result in serious problems.
Any foreign traveler wishing to enter Russia must apply for a Russian entry visa with the consulate or embassy. It is advisable, especially in the case of U.S. citizens, to apply for your visa with a Russian consulate or embassy in your country of citizenship. Doing otherwise can result in serious delays. Even when applying within your country of citizenship, applications should be submitted well in advance. The U.S. Department of State indicates that processing time for a Russian visa can take up to 20 days. Allow time for error and any issues that may arise. Please note that you cannot apply for a visa upon arrival; you absolutely must do so in advance.
Russian visas are often valid only for the length of your intended stay, as indicated by your sponsor. As a rule however, foreigners may not visit for more than 90 days in a 180-day period. This applies to business, tourist, humanitarian and cultural visas, though not employment or study visas.
Russia requires a visa to exit the country. If, for some reason, you fail to depart on time a Russian consular officer may issue you another visa at his discretion. However, this is only done when attempting to depart within three days of your original date. For overstays longer than three days, you will be detained in Russia until your sponsor intervenes for an extension on your behalf. It can take up to 20 days for to issue another visa.