I wrote this up for my father in law when he visited D.C. in 2014. Not sure if anything on here has changed since then but thought you might find some of it helpful:
1) White House
- Can take pictures from the outside gate.
Address:
1600 Pennsylvania Ave.
Washington DC, DC 20500
Plan to stay: Less than 1 hour
2) U.S. Capitol
- To view Congress in session, contact your representative or senator for passes.
- Whether or not you can get into the Capitol, the Capitol Hill grounds are worth exploring.
- To book a tour online you can do so here at the U.S. Capitol website: https://cvc.usedirect.com/CVC/#.VWeo7VmeDGc
- If you try for same-day tickets, arrive early (the visitor center opens at 8:30am).
Address:
East Capitol St NE & First St SE
Washington DC, DC 20515
Plan to stay: 1-2 hours
3) Supreme Court
- The Supreme Court is closed on weekends and holidays.
- When Court is not in session, trained docents give 30-minute lectures every hour on the half-hour.
- Entrance is free, but be prepared to go through security before entering.
- Court sessions are open to the public. There are two lines: to attend arguments, or to view for a few minutes. Arrive early, as space is limited.
Address:
First Street NE
Washington DC, DC 20003
Plan to stay: Less than 1 hour
4) Library of Congress
- This building is one of the most beautiful in D.C.
- There are many old publications including a Gutenberg Bible.
Address:
101 Independence Ave SE,
Washington DC,DC 20540
Plan to stay: 1-2 hours
5) The U.S. National Archives
- Where you can see the Declaration of Independence, Bill of Rights, Constitution, and Magna Carta.
Address:
700 Pennsylvania Avenue
Washington DC, DC 20408
Plan to stay: 1-2 hours
Memorials and Monuments
1) Lincoln Memorial and Reflecting Pool
- This is a bit further away from the center than the other monuments. Make sure to stop and take in the 2 mile view to the Capitol.
Address:
2 Lincoln Memorial Cir NW
Washington DC, DC 20037
Plan to stay: Less than 1 hour
2) Washington Monument
- An elevator takes you up to the top. Tickets are free but you have to get in line early.
Address:
2 15th St NW
Washington DC, DC 20007
Plan to stay: Less than 1 hour
3) Jefferson Memorial
Address:
South of the Washington Monument on Ohio Dr.
At the south shore of the Tidal Basin
Washington DC, DC 20242
Plan to stay: Less than 1 hour
4) Vietnam Veterans Memorial Address :
5 Henry Bacon Dr NW
Washington DC, DC 20242
Plan to stay: Less than 1 hour
5) National World War II Memorial
- You can see the Lincoln memorial in one direction and the Washington Monument in the other.
Address:
17th Street NW
between Constitution and Independence Avenues
Washington DC, DC 20006
Plan to stay: Less than 1 hour
6) Franklin Delano Roosevelt Memorial
- Takes at least 40 minutes if you want to read everything.
Address:
Off West Basin Drive
Washington DC, DC 20242
Plan to stay: Less than 1 hour
Museums
1) Smithsonian National Museum of Natural History
- Don't miss the Hope Diamond, located in the hall of Geology, Gems, and Minerals.
- The museum is open until 5:30pm daily, and until 7:30pm during summer.
- The IMAX movies tend to sell out, so if you wish to see one, buy your tickets in advance.
- This popular museum is almost always crowded. Visit early in the morning or late in the afternoon.
Address:
10th Street and Constitution Ave
Washington DC, DC 20560
Plan to stay: 2-3 hours
2) United States Holocaust Memorial Museum
- The museum is open everyday except for Christmas Day and Yom Kippur. Admission is free.
- During high season (March-August), timed passes are required to enter the permanent exhibition. Reserve them online in advance.
Address:
100 Raoul Wallenberg Plaza SW
Washington DC, DC 20024
Plan to stay: 2-3 hours
3) National Museum of American History
- As it's free, you can dip in and out. Wander around a bit, then go to lunch and come back.
Address:
Constitution Ave. NW
Between 12th and 14th Street Constitution Avenue
Washington DC, DC 20560
Plan to stay: 1-2 hours
A Little Outside Washington D.C.
1) Georgetown
- Get off M Street and walk around.
- Grab breakfast at one of the area's many eateries, before hitting the shops.
- Georgetown does not have its own Metro station. To get here, either take the Metro to Foggy Bottom and walk, or use the Circulator bus system.
Plan to stay: 2-3 hours
2) U.S. Marine Corps War Memorial
- If you're up for it, it's possible to walk here from Georgetown, and then on to Arlington Cemetery.
Address:
Arlington Blvd. and Meade St.
Arlington, VA 22211
Plan to stay: Less than 1 hour
3) Arlington National Cemetery
- Not to be missed is the grave of JFK (next to Jackie and two of her infant children), marked by an eternal flame.
- The Tomb of the Unknown Soldier pays homage to unidentified war heroes. Try to visit during the Changing of the Guard (every hour on the hour Oct-Mar and every half hour Apr-Sep).
- Visiting Arlington House on the hill will give you a good understanding of how the cemetery came to be.
Address:
Entrance at Arlington Memorial Bridge
Arlington, VA 22211
Plan to stay: 1-2 hours
Basilica of the National Shrine of the Immaculate Conception
- The Basilica of the National Shrine of the Immaculate Conception is the largest Catholic church in the US. It is open to the public and serves the Catholic University located next door to the church. This church has been visited and honored by two Popes. The main hall is massive and gorgeous. But the crypt on the lower level that is also interesting. Combining a visit to the Basilica and the Franciscan Monastary will fill half a day easily, plan accordingly in this city filled with lots to see and do.
Address:
400 Michigan Ave., NE
Washington DC, DC 20017-1566
Plan to stay: 1-2 hours