12TH & L STREETS LTD PARTNERSHIP
5 office properties in Washington, DC recorded to 5 owner entities mailing to 1150 CONNECTICUT AVE NW SUITE 801, WASHINGTON, DC. shared mailing address
At a glance
12TH & L STREETS LTD PARTNERSHIP is recorded as the owner of 5 office properties (5 parcels) in Washington, DC, totalling 2.2M sq ft of building area with $467.5M of assessed value. The holdings sit in 5 owner entities that share one tax-bill mailing address in WASHINGTON, DC — evidence of common ownership, not proof of it.
County assessment roll
Properties
| Building | Submarket | Sq ft | Assessed | Last sold | Tenants |
|---|---|---|---|---|---|
| 1800 G ST NW | Washington | 813.8K | $172.4M | — | 1 |
| 1100 L ST NW | Washington | 474.4K | $70.2M | — | 1 |
| 1025 CONNECTICUT AVE NW | Washington | 466.7K | $94.5M | — | 57 |
| 1150 CONNECTICUT AVE NW | Washington | 246.7K | $44.6M | — | 13 |
| 1425 K ST NW | Washington | 231.5K | $85.7M | — | 10 |
Names on the deeds
Owner entities at this address
- NORTHWESTERN DEVELOPMENT CO
- 12TH & L STREETS LTD PARTNERSHIP
- BLAKE DEVELOPMENT COMPANY
- NORTHWESTERN DEVELOPMENT COMPANY B
- BGW LP
How this group was built. These entities share a mailing address but not a name root. That often means one sponsor, and can also mean a shared law firm, accountant or tax servicer.The county records an owner and a mailing address for every parcel; this page collects the office parcels whose owners mail to the same address, and counts buildings rather than parcels using the county's own condo-to-building link. Lease terms, rents and the identity of a manager acting for the owner are not public records and are not shown.
Where are 12TH & L STREETS LTD PARTNERSHIP's office buildings?
All 5 properties are in Washington.
The largest is 1800 G ST NW in Washington at 813.8K sq ft.
Recorded build years run from 1965 to 1975.
How large is this portfolio within Washington's office market?
Its 2.2M sq ft is 1.05% of the 212.1M sq ft of office building area on the Washington, DC roll.
Its $467.5M of assessed value is 0.60% of the metro's office total.
It holds 5 of the metro's 1,761 office buildings.
Frequently asked questions
How many office buildings does 12TH & L STREETS LTD PARTNERSHIP own in Washington?
5 office properties (5 parcels) on the Washington, DC roll, counted by building rather than by condo parcel.
What is 12TH & L STREETS LTD PARTNERSHIP's largest office building?
1800 G ST NW, Washington — 813.8K sq ft, assessed at $172.4M.
What are 12TH & L STREETS LTD PARTNERSHIP's office properties worth?
Their combined assessed value on the current Washington, DC roll is $467,484,534. Assessed values are taxable-roll figures, not market prices.
Are these properties owned by one company?
These entities share a mailing address but not a name root. That often means one sponsor, and can also mean a shared law firm, accountant or tax servicer. 5 owner entities share the mailing address. It is evidence of common ownership, not proof of it.
Related
Everything here comes from public records, and public records go stale. If you know better, say so.
Data provenance — public records only
- Washington, DC — Integrated Tax System public extract (owner names, mailing addresses, assessments), CAMA commercial and daily sales tables, Basic Business Licenses (suite-level premises; the universal catch-all licence was repealed Oct 2025, thinning the roll thereafter), and DOEE energy benchmarking.
Every fact on this page is drawn from the government records above — no listing sites, no scraped platforms, no third-party images. Facts from public records are uncopyrightable; each tenancy row carries its source and match confidence. Records can lag reality — a business-tax receipt or registration at an address is evidence of occupancy, not a lease confirmation.
Dataset updated . Derived from public data sources.
About this data
Source: Integrated Tax System public extract (Washington, DC), as published September 20, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “12TH & L STREETS LTD PARTNERSHIP — Washington office property holdings”, https://buildingcensus.com/offices/dc/owners/12th-l-streets-ltd-partnership-1e0738 (data as of September 20, 2026).