Location: The courthouse is in fact Santa Monica City Hall which does have some court rooms. Submitted by Eric Cooper, 3/30/2009. Pictures here and here.
+ The fictional "Manzana Valley" is once more the setting for Perry's case in ep#186, TCOT Decadent Dean. The "Manzana County Court House" seen in that episode (23:09) is an older and much smaller building than the courthouse used in this episode. Added by Gary Woloski, 2/5/14.
+ Much of this episode seems to have been filmed at the Green Tree Golf Course, Victorville, CA. You can see the attractive modern building on their website. 01/04/15 Welshwoman.
+ Wow!! That little river must have been working overtime: what was a cacti studded desert in the episode seems to be a lush greensward today. Submitted by Notcom, 010616.

There's something strange going on here. On the website for the Green Tree Golf Course, it says that it was completed in October of 1963. But this episode aired December 30th, 1961. One explanation could be that there was a smaller course, maybe only 9 holes, that existed prior to the opening of the course as an 18 hole course in 1963. Otherwise, it must have been filmed at a different course, or some time travel was involved. Submitted by Paul's Operative. 1/10/2024.

According to the IMDb, the real name of actor Dirk London is Ray Boyle. Submitted by gracep, 12/7/2010.
+ and doesn't he look like Cornell Wilde? jfh 12Dec2023

Although credited, Ray Collins (Lt. Tragg) did not appear. Submitted by gracep, 12/7/2010.

Both Harry Carey, Jr. and Pat O’Malley were regular cast members in Disney’s Spin and Marty series. Submitted by Masonite, 7/11/2011.
It is hard to disassociate Harry Carey Jr. from John Wayne (9 films), John Ford, and Westerns in general. Joe B. 3/30/19.

+ Don't leave out the 'J': Just as Michael J. Fox had to add the 'J' to his name to distinguish himself from Perry Mason actor Michael Fox whose career was active through 1995 just a year before his death, J. Pat O'Malley had to have a different name than Pat O'Malley, an actor whose career spanned the years 1908-1962. The two O'Malleys paths came close on The Twilight Zone: While J. Pat O'Malley appeared on four episodes, Pat O'Malley only appeared on three. Submitted by Wiseguy70005, 4/20/15.

Some other cast appearances: Paul Fix appeared on the original Star Trek as the first doctor on Capt. Kirk's Enterprise before DeForest Kelley's Dr. McCoy appeared. (John Hoyt had appeared as the doctor on Capt. Pike's Enterprise. All three actors have appeared on Perry Mason.) Sarah Marshall (later wife of Karl Held) played Capt. Kirk's former love interest in "The Deadly Years" in 1967. Both actors also appeared on The Twilight Zone, Paul Fix in 1964's "I Am the Night-Color Me Black" and Sarah Marshall as the mother of the "Little Girl Lost" who got lost in another dimension in 1962. Philip Ober appeared in 1964's "Spur of the Moment" and J. Pat O'Malley played "The Fugitive" in the 1962 episode along with Wesley Lau. June Vincent appeared in a 1967 episode of Ironside and Paul Fix in a 1970 episode. Submitted by Wiseguy70005, 4/20/15.

Paul Fix and William Hopper were reunited in the 1956 movie The Bad Seed. jfh 17Oct2017.

Word of the day: Perry Mason used the word “riparian,” which refers to river banks and/or adjacent wetlands. Submitted by gracenote, 7/12/2011.
+ See"geographical questions" Comment, below, for illustrations of "riparian". Added by Gary Woloski, 2/7/14.

Deliciously dapper David Gideon (Karl Held) delights us again with his carefully memorized detailings of legal doohickeys and, of course, his dandy dress and dazzling smile. Eight appearances down, one to go. Submitted by gracenote, 7/12/2011.

Character Names: Although Paul Fix is credited here only as “Prosecutor,” we know from Fix’s other four PM appearances that his character’s last name was always Hale, and his first name was either Jonathan (“TCOT Barefaced Witness”) or Darwin (“TCOT Angry Mourner”). He was mainly used when Perry would try a case outside of the city. Submitted by cgraul, 11/9/2011.
Harry Carey, Jr. is Paul Fix's son-in-law. Paul Fix played Micah the sheriff on The Rifleman, submitted by OLEF641, 1/18/2017

CARS. (1) 1961 Mercury Commuter 4-door station wagon, white, "Manzana Valley Inn" logo on doors, Lic No VNE 546, Matt Lambert ("Uncle Matt" to Judy). Half-way through the episode Della drives this car in a re-enactment of events to determine timings.

One background car: the white 1961 Ford Fairlane 4Door Sedan in opening sequence parked beside the "MANZANA VALLEY AIRPORT" sign. Added by Gary Woloski, 2/18/13.

The Bomb Plot. An item on page 14 of the Appleton, Wisconsin Post-Crescent of December 20, 1961 asserts that elements of this episode's plot were lifted from a real-life murder that occurred in Wisconsin on 27 Dec 1922. The article begins:

"(MADISON) Like many another crime sleuth before him, TV's Perry Mason has discovered and made use of the wood experts at the U. S. Forest Products Laboratory (FPL) here. In fact, a real life murder case that an FPL scientist helped solve a quarter century ago is the basis of "The Case of The Roving River", which will be solved by Mason for the edification of TV's millions of mystery addicts Saturday, Dec, 30. . . . In the plot, a forest ranger makes a hurry-up flight by charter plane from California to Madison with evidence gathered at the murder scene. What FPL's wood and glue experts tell him about the fragments he shows them constitutes the testimony he later gives on the witness stand as Mason's star witness in--you guessed it--a murder trial. A onetime Madison resident now living In Los Angeles, Calif., will have a deep personal interest in the show. He is Arthur Koehler, wood technologist, who long played a starring role on the research staff of FPL--and in some of the nation's most bizarre cases." (emphasis & links added, GW)

The Wisconsin murder occurred in the home of County Commissioner James Chapman in Wood County near "the small city of Marshfield . . . two days after Christmas 1922". A home-made bomb which had been sent through the mail exploded while being unwrapped, maiming Chapman and fatally injuring his wife. It didn't take long to identify the prime suspect as farmer John Magnuson, who was in dispute with the County Commission over imposition of water drainage measures and resultant taxation. Magnuson, dubbed the Yule Bomber (full story at the link), was charged with first-degree murder in the death of Mrs Chapman. The trial opened on 15 Mar 1923 at Wisconsin Rapids. Arthur Koehler was one of several scientists called to give expert testimony in their own field. Magnuson was found guilty on 31 Mar and sentenced to life imprisonment. He served most of his sentence at the state hospital for the criminally insane, escaping temporarily for what he called a "holiday" in 1940. After being paroled in 1952, Magnuson died at age 78 in 1957.
      The Wood Forensics of Arthur Koehler were also featured in the Feb 1935 issue of Popular Science pages 14,15,114.
      The common elements in the two stories (the roving Wisconsin River & the roving river of this episode; disputes involving land rights & river water; the bombings; the late-December timings; and use of FPL experts) support the credibility of the Post-Crescent article. It also seems likely that the seeds for the newspaper article must have been planted by Sam Newman, Paisano Productions or CBS.
      I believe that it's a fantastically bizarre coincidence that the newspaper article preserved on the internet was published in "Appleton" WI and that the "Appleton Land Company" is the likely root of the name of "Apple Valley" CA which, in turn, I believe is the real-world location of the "Manzana Valley" of this Episode#138. "Manzana" (sp.) = "Apple". Added by Gary Woloski, 5/5/14.
Map showing Marshfield - Wisconsin Rapids - Appleton here. Madison can be seen directly to the South of the highlighted route.

Raymond won the 1961 Emmy for Outstanding Performance by an Actor in a Leading Role [IMDb Awards]. Mike Bedard 3.8.15.

This is the only PM appearance for Sarah Marshall, who was born in London, England, in 1933. Sarah Marshall married PM regular Karl/Carl Held in 1964 and they remained married until her passing in 2014...MikeM. 10/11/2016

This is the third of five PM appearances for Bruce Bennett, who won a silver medal in the shot put at the 1928 Olympics. Bruce Bennett passed in 2007 at the age of one hundred...MikeM. 10/11/2016

+The handsome Bennett also appeared as Tarzan in the 1930s, under his real name, Herman Brix. He lost the role of MGM's Tarzan to Weissmuller due to a broken shoulder, but played a well-spoken, true-to-the-books Lord Greystoke in The New Adventures of Tarzan, released as both a feature and a serial in 1935. Worth watching! Submitted by JazzBaby, 3/6/2019.

This is the final of five PM appearances for June Vincent, who also appeared in five episodes of Have Gun - Will Travel...MikeM. 1/17/2017

Sarah Marshall was the daughter of renowned English actor Herbert Marshall and his actress wife, Edna Best...MikeM. 1/17/2017

+ OK, actress Sarah Marshall's British accent is genuine enough, but how did the character Judy acquire her accent? I don't think we heard that she was brought up overseas, or whatever. JohnK, 9 December 2021

This the first of three PM appearances for Kelly Thordsen. He would play Sheriff Watson in his second appearance. He reprised the role of Sheriff Ward Vincent in his third appearance...MikeM. 2/6/2018