This guide was meant to be a resource for anyone pursuing 100% completion in this game, and a place where you can find any in-depth online guide for all of the many, sometimes unbearably tedious challenges and missions that you have to complete.

The format for this guide is based off of the Progress tab of the in-game menu, and the list of everything in it is ordered as such. A lot of the sections for the tasks in this guide will just be a link leading to an online guide from a number of different websites that detail anything that you need to know to complete their respective task. If I found that I needed to add more detail, the links to each tasks' respective guide will be next to my description. If the task doesn't require a large amount of detail, there is just a little blurb of writing under their label.

Additionally, here is an interactive map that you can use for finding locations for many of the things that you will need to find or collect throughout your journey to 100% completion. You can simply use this map for the collectable quests in place of the links I have provided in each section of the guide. I often found it easier to just use this map instead of navigating the janky UI of some of these sites.

RDR2 Interactive Map[rdr2map.com]

Missions

All you have to do is complete the main storyline, and this will be checked off the list.

Strangers

To complete this, you will need to complete 10 Stranger mission strands. Note that you have to complete all of the missions for each stranger for them to count for this list. You'll most likely find plenty of these missions while adventuring around the map; whenever you see a "?" on the map, go check it out and work on completing all of the missions for that person from there on out.

Bounties

You have to complete 5 bounties. Whenever you enter a new town, there will be a bounty either near the sheriff's office or the post office. Do them, and you're done.

Chance Encounters

Every so often, you'll see a white circle on your minimap near your location when riding around. These are Chance Encounters. Go check them out each time, and deal with them as you see fit. Do 25 of these, and you're done.

Bushwacked

Survive/Encounter 1 Gang Ambush. You will get this one naturally, as you will probably be stopped by one of the gangs at some point. Deal with them, and you're done.

Gang Hideouts

You need to capture (meaning that you kill everyone inside) 6 Gang Hideouts throughout the map. 4 of these are unmissable, as you capture them in the main story, and the other 2 can be done during the Epilogue.

Gang Hideouts Locations[www.powerpyx.com]

Points of Interest[www.rdr2.org]
You only need to find 1 one of these on the map; these include anything that Arthur can inspect - he will then write in his journal. If you want to find a specific POI, see the guide linked above.

DO NOT CLICK UNLESS YOU HAVE COMPLETED THE MAIN STORY

Grave Locations

Cigarette Cards

To initiate this quest, go to Flatneck Station after you complete the mission there for Reverend Swanson ("Who is Not Without Sin"). There will be a stranger mission marker there. Go through the cutscene, and then proceed.
To do this in the most efficient manner, you will need quite a bit of spare cash. The easiest way to get a full set of cigarette cards is to go into a store, stand by the premium cigarettes (not in the catalogue) in first person, and buy two packs. You will get two cigarette cards from this. After this, go into your satchel and discard all of your premium cigarettes. Buy two more packs, and rinse and repeat until you have a full set. This may take a decent amount of cash (most likely in the hundreds of dollars). You still get credit for the challenge if you mail the card set to the guy for the money.

Dinosaur Bones Locations[www.polygon.com]

To initiate this quest, you'll have to find a woman named Deborah MacGuiness, who is located south of the H in The Heartlands on the map. After talking with her, you can go around the map and find all 30 of the locations for the dinosaur bones.

Legendary Fish Locations + Tips[www.polygon.com]

To initiate this quest, go see a man named Jeremy Gill at Gill Landing on the southern shore of New Hanover, southeast of Flatneck Station and just west of the Lemoyne border.

Exotic Requests Guide (Duchesses and Other Animals)[www.powerpyx.com]

You can get this quest at the beginning of Chapter 4, and you'll have to talk to a man named Algernon Wasp at the north end of Saint Denis, east of the E in Lemoyne.

Rock Carvings Locations[www.powerpyx.com]

To start this quest, you'll need to find a man named Francis Sinclair, who is living in a small cabin west of Strawberry.

Hunting Requests Guide[www.powerpyx.com]
To start this quest, go to any of the post offices in the towns/cities throughout the map, and find a poster somewhere on the wall of the office about a woman looking for some animal specimens to be shipped to her via mail. It's important to note that you are going to need a lot of Small Game Arrows for this quest, so make sure to stock up on those. You also are going to need a Varmint Rifle - the reason being that all of the carcasses (NOT pelts) need to be in perfect condition. This means that you are going to have to use the correct weapons for each kill in order to preserve the animal. It is also helpful to get the Buck Antler Trinket, which improves the quality of the animal when you kill it. In practice, this mitigates the likelihood of getting a lower quality pelt from unclean kills (kills to non-vital organs, even with the correct weapon), and increases the likelihood of getting a higher quality pelt from a lower quality animal (ex. getting a "perfect" pelt from a "good" animal). For most, if not all, of the requests, there will be one big animal carcass that you need to store on your horse - make sure to get this one last, as the game won't let you mail the request until you have all of the carcasses for that respective request. Once you get all of the carcasses for each request, head to a post office to mail them off; then wait for the next request to come in by mail shortly thereafter.

Treasure Hunter (Guide)[www.powerpyx.com]
For this, you only have to complete 1 Treasure Hunter chain, meaning that you just have to get all three of the maps and the treasure for one chain. You can easily do this with the Jack Hall treasure map that you can get early on in chapter 2, but if you want to try something else, you can complete any of the chains in the guide listed above.

Dreamcatcher Locations[www.polygon.com]

Once you find your first Dreamcatcher location (it can be any of them), a quest will pop up in your log to find the other 19 locations.

Animals
For this one, you have to discover 50 species of animals. Just study animals as you come across them, and it will come naturally. If you want to get the Zoologist and Skin Deep Achievements while you are doing this, there is a guide and video linked below:
Zoologist and Skin Deep
Animal Locations Guide [www.trueachievements.com]

Equipment

You have to get 10 different pieces of equipment. You will just get this over time as you play through the story. Equipment includes things like tools and accessories for Arthur.

Fish

To complete this, you have to discover 10 different species of fish. You will more than likely complete this while you are fishing for the legendary fish, but make sure to study each type of fish surrounding the legendary fish's location and you will check this off naturally.

Gangs

All you need to do is encounter each of the 6 main gangs in the game. You should encounter all of them naturally as you progress through the main story and epilogue.

Horses
You have to discover 10 different breeds of horses. Study the horses that you come across in towns, and you will get this pretty quickly.

Plants

You'll have to collect 20 out of the 43 total plant species that are littered throughout the map. As you explore the map, watch out for herbs that you can pick (you can check your surroundings with Eagle Eye - there will be white spots hovering above anything that you can pick). Doing this, you should be able to complete this naturally as you progress through the game.

Herb Locations[www.powerpyx.com]

Weapons

To complete this, you have to collect 48 different weapons throughout the game. You'll get a lot of these as you progress through the story, but here are some locations for unique weapons that you'll need to finish them off.

Unique Weapons Locations[www.powerpyx.com]

Reach maximum Health, Stamina, and Dead Eye

Leveling Health, Stamina, and Dead Eye Cores[www.powerpyx.com]

Reaching maximum health and stamina should come pretty naturally, but maxing out dead eye may take a bit longer. Over time, you will acquire experience for each of these, but certain activities or consumables will help improve these stats faster. See the link above.
Note: To actually max out each stat (so it will count for this challenge), you have to first complete all 9 of the challenge chains and then buy all of the challenge-exclusive gear from the trapper, so this will come after you have done that.

Horse Bonding

Just keep using one horse for a while, keep it fed, and press G every so often while riding to check this off the list. It won't take very long.

Challenges

There are 9 sets of separately-themed challenges, with each of them having 10 stages with different tasks that you need to complete to progress through them. Some of these can extremely irritating, so I would advise that you spread these out throughout your playthrough to avoid burnout. I find that it is easy to lose motivation when you are stuck doing the boring and tedious stuff for too long at a time.

Herbalist Challenges[levelskip.com]

Master Hunter Challenges[www.gamesradar.com]

Survivalist Challenges[www.gamesradar.com]

Gambler Challenges[www.gamesradar.com]
Side note for Gambler Challenge 9: For me, this was the single most irritating part of getting 100% completion, but if you simply leave the dominoes match before you lose, your win progress won't reset. This saved me a lot of frustration, but this challenge still takes a long time unless you actually know how to play dominoes, unlike me. Also make sure that you only have one opponent, as it makes winning much easier - I would recommend playing at Saint Denis and reloading your game until you just have one.

Sharpshooter Challenges[www.gamesradar.com]

Horseman Challenges[www.gamesradar.com]

Weapons Expert Challenges[www.gamesradar.com]

Bandit Challenges[www.gamesradar.com]

Explorer Challenges

All you have to do is find 10 different treasure maps - each stage of this challenge is the same. The easiest way to get this is simply to do three different treasure map chains (there will be 3 maps that you have to find for each), and at some point collect Chick Matthews' debt for Leopold Strauss in Chapter 2. He will give you a treasure map that shows where his debt money is, and that will count for one stage of the challenge. See the link below for treasure map locations.

Treasure Maps Guide [www.powerpyx.com]

Shacks

You only need to visit 5 of these in order to mark off this one. You'll probably get this naturally by exploring the map.

Shack Locations[www.usgamer.net]

Legendary Animals

Legendary Animal Locations + Tips
You only need to hunt down 5 of these animals to fulfill the requirements.

Table Games

Play 1 game of Poker, Blackjack, Dominoes, and Five Finger Fillet. You can find each of these in:

Poker: Valentine Saloon

Blackjack: Rhodes Saloon

Dominoes: Gang Camp, Train Station at Emerald Ranch

Five Finger Fillet: Table near the fast-travel post in Strawberry

Ranters, Ravers, and Campaigners[segmentnext.com]
You should be able to get this pretty early on with some exploring, and you also shouldn't need to use a guide; If you happened to miss some of them, their locations are above.

Bath

Go to any town and order a bath at either the hotel or saloon.

Show

See any motion picture or performance. The easiest way to complete this is to go to see a movie in the tent just south of the stables. You can also go to the theater in Blackwater or Saint Denis.

Theater

See a show or movie at the theater in Saint Denis.

Recipes

You're going to have to do some crafting for this one. Craft 1 meal from a cooking recipe, 1 tonic, 1 type of ammunition, 1 hunting item, 1 horse care item, and 1 weapon. You should have most, if not all, of these unlocked by default, but if you don't, you can go to the fence and purchase a recipe from there. If you pick herbs when you see them and have some meat on you, you should be able to cover most of the stuff needed for this without having to seek it out.

Robberies

Robberies Guide[www.metabomb.net]

You should at least be able to get one homestead robbery naturally (one of them is with Javier in Chapter 2), but you also need to rob 1 coach, 1 train, and 1 shop. Some tips and locations for these three are in the guide above.

Once you have checked off all of the segments in the total completion tab, you should have gotten the "Best in the West" achievement, and have gotten 100% completion.
Attaining 100% completion for this game can be a real pain sometimes, but I think that it is all worth it due to just how much this game has to offer in nearly all departments. If you found my guide helpful, I appreciate the fact that you decided to use it. My goal was to compile everything that you could ever need for getting 100% completion in one place, so looking anything up wasn't necessary aside from troubleshooting bugs (that, hopefully, no one will experience).