Jenkins Run Drain Tunnel

In Urban Exploration - Drains/Sewers by Ronnie K

| Jenkins Run Storm Sewer Tunnel | Jenkins Run Stream | Guilford Avenue / Jones Falls Conduit Construction Tunnel|

Jenkins Run Stream is an ancient, forgotten underground urban stream, covered over and buried in culvert. Its construction spanned over a period of 30 years related to lack of funds. Its construction had numerous pitfalls and delays related to the torrential nature of this stream during periods of extreme downfall. Compounded complications included poor workman ship which required the reworking of the drains foundation at one point.

The Jenkins Run Storm sewer is responsible for draining Jenkins Run Stream, Carter Alley Stream and now in modern time, a large impermeable area, with many small lateral drains. A a remarkable interceptor, with a robust history that is not even touched in this writing. It is responsible for draining 2 streams (ref .). It serves as a drain point Union Railroad tunnel. It networks continue to traverses near the graves laid in the Greenmount Cemetery. It is quite well preserved. Stepping into here is like stepping into time portal into the early 1900’s sewer works. An excellent preservation of the past. The upper portions being constructed in the 1880’s, more work put into it after violent flooding and shotty worksmanship in the 1890’s. The lower interceptor section, is the final re-engineering of the stream leading to its dark underground outfall. It was finished near 1912, during the city’s drain laying Gymboree. It was during this time that the final outfall tunnel (before it was an outfall) was used as a construction tunnel to haul materials in and out of the tunnel. At its completion, the loathsome CSO / SSO #72 was placed. It boasts a significant steep grades, staircase / drop falls, full brick tunnels, brick arch horseshoe tunnels, masonry granite, overhead flume, long curves, numerous stone granite side drains and a CSO/SSO purge discharge point. In the upper mid section of the tunnel, houses a sizable double junction chamber. The western tunnel is old granite stone construction drain, that doesn’t work well. Standing water and old air back in there . The eastern shaft is the continuation of Jenkins Run. Basically, the further you go back, the older is gets. And the Jenkins Side goes back deep, well above North Ave and with its limited surface access presents the most fearsome environment in an already dangerous city.

Jenkins’s Outfall
10 foot outfall storm sewer

Historical Quotations:

“The Jenkins Run Drain empties into the Jones Falls between Preston and Hoffman streets runs northerly via Carter alley to a point 135 feet north of Lafayette avenue and thence northeasterly to a point in Boone street north of Twentieth street For 3,270 feet to a point in Walcott street it has cross sections of from 163 to 49 square feet and is built with a segmental arch Above this it is circular and 10 feet 6 inches in diameter It drains nearly 900 acres including Homestead and that part of Waverly east of the York Road It has two principal branches

  1. In Hoffman street to Home wood avenue 4 feet in diameter
  2. In Girard avenue to Barclay street 3 feet in diameter .”

(ref. 1)

“The heading of the tunnel under Guilford avenue has been extended from the entrance of the retaining wall between Biddle and Chase streets to a point 250 feet beyond Preston street a total distance of 8oo feet The heading of the Jenkins Run Sewer tunnel has been extended through to meet the large tunnel a distance of 430 feet The rock excavated from this tunnel is being crushed and used to form the concrete conduits in the bed of the Falls below Chase street.”
(ref. 2)


Exploring a massive 12 foot drain, from within another massive drain requires knowledge, planning, physical fitness and wit. Such a treacherous adventure should not be carried out by a casual urban explorer, the ill prepared or weak hands.  When this drain was discovered, research seemed to point that this tunnel was draining what was once known as “Jenkins Run”.  An ancient stream that was buried & covered over well over a century ago and is the largest buried stream outfall in the Jones Falls Conduit system. Every time this tunnel was passed, a strong curiosity beckoned for its penetration.  What lies inside was an unknown, granted its overall large size, one could only assume it was the beginning of a large storm sewer network.  If subsequent research was on point, it seemed that sizable chambers may lay within. Years later, infiltration was undertaken and the curiosity laced with patience & preparation paid off. A strong wind pours out of this tunnel, however, it was decided that subsequent exploration would require a Multi-Gas Detector.

The Buried Outfalls Entrance into the system

The tunnel briefly bears right before straitening out, most likely for hydrological considerations as it meets the underground Jones Falls river
jf conduit jenkins run sewer
Jenkins run and Carter Alley Junction Chamber

Looking up the stairway towards the later portion of it. 

The original Jenkins Run diversion chamber photo source (ref .2)

Jenkins Run Sewer
A quick video glimpse of Jenkins Run Outfall


  1. Report of the Sewerage commission of the city of Baltimore , 1897
  2. Baltimore Sewerage Commission Annual Report, 1913