Company Names, addresses, dates¹:
  Dr Pepper Bottling Co, 6101 Blair Road NW (1938-1965)
  Tru Ade Bottling Co, 6101 Blair Road NW (1942-1969)
  Mason's Root Beer Bottling Co, 6101 Blair Road NW (1957-1962)

Notes:
I'm not sure if Dr Pepper and Tru Ade were connected, but in Washington DC, they were both bottled at the same address (6101 Blair Road NW). Mason's root beer was also bottled at that address, but I've never found a Masons root beer bottle that actually said "Washington DC" on it.
Circle-A brand doesn't show up in any DC directories, but the bottle says that it was produced by the Dr Pepper company.
Some city directories for Seven-up say that they were "bottlers of Dr. Pepper since 1966" and "bottlers of Tru-Ade since 1966"¹.

Bottles:

(enlarge)	This is a clear 8.1" crown top bottle with debossing (letters are indented rather than sticking out). The back has a clock with hands pointing to 10, 2 & 4. This was part of an ad campaign with the slogan "Drink a Bite to Eat at 10, 2, and 4 O'clock" based on a study that indicated people need a glucose lift at those 3 times. The bottle is marked: front: Dr. Pepper / GOOD FOR LIFE back: (picture of clock with hands on 10, 2 & 4) / 6 1/2 OZS bottom: WASHINGTON / DC
(enlarge)	This is an 8" clear crown top bottle with some embossed design (3 rings around the neck and circles with A's in them), and black on white markings: front: CIRCLE "A" BRAND / (letter 'A' in a circle) / BEVERAGES back: CIRCLE "A" BRAND / THE SIGN OF / HIGHEST / QUALITY / BEVERAGES/ 7 FLUID OUNCES / PRODUCED BY / DR PEPPER BOTTLING CO / WASHINGTON DC
(enlarge)	Similar to above but it's green and doesn't have the emobssed design. It's an 8" green crown top with black & white markings: front: CIRCLE "A" BRAND / (letter 'A' in a circle) / BEVERAGES back: CIRCLE "A" BRAND / THE SIGN OF / HIGHEST / QUALITY / BEVERAGES/ 7 FLUID OUNCES / PRODUCED BY / DR PEPPER BOTTLING CO / WASHINGTON DC
(enlarge)	This is an 8.5" clear crown top bottle with a corn-cob like pattern shape on top, and a white & red ACL that says: front: PASTURIZED / TRU ADE / Not Carbonated / VACUUM SEALED / CONTAINS FILTERED WATER, CONCENTRATED FRUIT JUICE EQUAL TO 15% / NATURAL JUICE, SUGAR, FLAVOR, CITRIC ACIC, & ARIFICIAL COLOR back: NET CONTENTS 7 FL OZS / NO PRESERVATIVE USED / BOTTLED BY / TRU ADE BOTTLING CO / WASHINGTON, D.C.
(enlarge)	This is the "king-sized" version of the bottle above. It's a 9.7" clear crown top bottle with a corn-cob like pattern shape on top, and a white & red ACL that says: neck: KING / SIZE / TRU Ade / TRU Ade front: PASTURIZED / TRU Ade / Not Carbonated / VACUUM SEALED / CONTAINS FILTERED WATER, CONCENTRATED FRUIT JUICE EQUAL / SUGAR, FLAVOR, CITRIC ACIC, & ARIFICIAL COLOR back: NET CONTENTS 10 FL OZS / NO PRESERVATIVE USED / BOTTLED BY / TRU ADE BOTTLING CO / WASHINGTON, D.C.

	This is a wooden carton for Tru Ade soda from Washington DC.
	This is a purple & white bottle cap that says: front: Grape / TruAde / not carbonated edges: WASHINGTON SEVEN-UP BOTTLING CO. WASHINGTON, D.C. LESS THAN 1/10 of 1% SODUM BENZOATE & POTASIUM SORBATE Some city directories for Seven-up say that they were "bottlers of Tru-Ade since 1966", so I presume this cap is from 1966 or later.