To prepare, Matthew McConaughey created a four hundred fifty-page analysis, the "Four Stages of Rustin Cohle", to study his character's evolution over the course of the story.

Episodes averaged 11.2 million viewers, making it the most watched first season of an HBO original series since Band of Brothers (2001).

In the first season, Matthew McConaughey plays an Atheist, while Woody Harrelson plays a Christian. In reality, their world views are reversed, with McConaughey being a Christian and Harrelson being an Atheist.

According to Matthew McConaughey, the entirety of Rust Cohle's interview scenes was shot in one day; about twenty-eight pages of a four hundred fifty page season one script was filmed over the course of an eighteen hour work day.

Christian Bale and Jessica Chastain were pursued for lead roles in the second season of the show, but both passed on the project due to the significant time commitment the show would've required.

Rust Cohle is based on a high school teacher in Arkansas, who also worked on the police force.

It is one of the highest rated television shows of all time, and one of the few shows that generated more than ten million viewers, despite it not being for family audiences.

Series Creator Nic Pizzolatto wrote the first season by himself, without any input from a writing staff (which is unusual for a major American television series). For the second season, he hired author Scott Lasser to help break stories.

The first season was entirely shot on film.

Over the course of the first season, Rust Cohle (Matthew McConaughey) smoked forty-nine cigarettes and drank eight beers on camera.

The city of Vinci is based on the corrupt city of Vernon.

David Cronenberg was offered the opportunity to direct the first episode of the second season, but he declined because he felt the script was poor.

The music playing underneath the title sequence in season two is the song "Nevermind" by Leonard Cohen. For each episode, the edit of the song is slightly different, highlighting various sections of the song and its lyrics that may or may not be relevant to that particular episode. One of the episodes' title, for example, ends with the words "I live among you, well disguised." This is different to season one, where the title music is edited the same way for all episodes.

True detective season 1 was originally planned as an HBO original mini-series but HBO was so impressed they decided to turn it into a TV show.

According to Nic Pizzolatto, all of the nude scenes in season one were pay cable mandated. Even stating he would be happy with no nudity.

One of Creator, Showrunner, and Writer Nic Pizzolatto's initial remarks about the second season were that it is set around the "secret occult history of Los Angeles' transport system". He later admitted that this was a joke in response to the frustration of constantly being asked the question "what is season two about" so often and so early in the writing process. He found it funny that the quote actually got traction, so did nothing to debunk it.

Creator and Writer Nic Pizzolatto acknowledged the strong influence of Thomas Ligotti's and Emil Cioran's philosophical writings on the series: "I'd already been reading E.M. Cioran for years and consider him one of my all-time favorite and, oddly, most nourishing writers. As an aphorist, Cioran has no rivals other than perhaps Nietzsche, and many of his philosophies are echoed by Ligotti". (2014)

The title credits of the fourth season of Key and Peele (2012) directly spoof the season one title credits of this show. Also, in every episode before each skit, Key and Peele are seen driving through the desert having philosophical (albeit humorous) conversations, in another direct spoof of the long and frequent scenes of driving and conversations in season one of this show.

Several scenes of the second season had to be re-shot, due to the cast not being able to understand Colin Farrell's speech during some of his drunk scenes. Vince Vaughn even cracked jokes about how it sounded like he was growling at a wall.

Woody Harrelson and Matthew McConaughey are natives of Texas.

Colin Farrell gained twenty pounds (nine kilograms) for his character Ray Velcoro.

Matthew McConaughey and Woody Harrelson appeared in Edtv (1999) and Surfer, Dude (2008).

Jessica Biel and Malin Akerman were among the actresses also considered for the role of Detective Ani Bezzerides.

The pocket knife Rust carries is a Smith & Wesson 1st Response.

Rosario Dawson, Elisabeth Moss, Brit Marling, Oona Chaplin, and Jaime Alexander were considered for the role of Detective Ani Bezzerides. Kelly Reilly and Abigail Spencer auditioned to play Ani before being cast as Jordan Semyon and Gina Brune, respectively.

When Cohle is brought beer, and starts drinking it, the name is visible. The beer is called Lone Star, a popular beer in Texas. Also, Matthew McConaughey appeared in Lone Star (1996).

Friday, November 7, 1980, was the night Steve McQueen died. This is all correct in season 3, episode 1, except for the full moon. It was actually in new moon phase

Although the second season is set in California, and the characters that Colin Farrell, Rachel McAdams, and Taylor Kitsch play are Americans, none of the performers are American in real-life. Colin Farrell is Irish. Rachel McAdams and Taylor Kitsch are Canadians.

Rachel McAdams and Kelly Reilly appeared in Sherlock Holmes (2009) and Sherlock Holmes: A Game of Shadows (2011).

In the first season, the Sheriff's last name was Tate. Heck Tate is the Sheriff in the famous novel and the movie, To Kill a Mockingbird.

Matthew McConaughey and Alexandra Daddario appeared in The Texas Chain Saw Massacre film franchise. Matthew played in Texas Chainsaw Massacre: The Next Generation (1994) and Alexandra in Texas Chainsaw 3D (2013).

Vince Vaughn and Rachel McAdams appeared in Wedding Crashers (2005).

The two cars that Detective Ray Velcoro (Colin Farrell) drove were Dodge Chargers.

In season two, Taylor Kitsch played a military veteran named Paul Woodrugh. Kitsch previously played a Navy S.E.A.L. in Lone Survivor (2013) and a former S.E.A.L. in Savages (2012).

Season two is set in the fictional city of Vinci, which is really meant to be Vernon. Vince Vaughn's father and son are both named Vernon.

Woody Harrelson and Lili Simmons share the same birthday.

Timothy V. Murphy, Tory Kittles, and Brad Carter appeared on Sons of Anarchy (2008).

Ritchie Coster and Christopher James Baker appeared in The Blacklist (2013).

Creator Nic Pizzolatto contemplated another ending for season one, in which Marty and Rust didn't leave the maze and were never heard from again, but in the end, he decided to give them a happy ending.

Season one is part of the sub genre of Cthulu Mythos. Many references to Robert W. Chambers collection of short stories "The King in Yellow" appear in the show, such as Carcosa, The Yellow King, and black stars. The original description of Errol Childress, the "green eared spaghetti monster", is a reference to H.P Lovecraft's Cthulu. Lovecraft was also influenced by "The King in Yellow".

In season two, the dream sequence at the beginning of episode three foreshadows Detective Ray Velcoro's death at the end of the season.

So far, season one is the only season where none of the main characters are killed.