diff --git a/runatlantis.io/docs/custom-workflows.md b/runatlantis.io/docs/custom-workflows.md
index ce3a77bf87..1f207ab0b8 100644
--- a/runatlantis.io/docs/custom-workflows.md
+++ b/runatlantis.io/docs/custom-workflows.md
@@ -136,32 +136,36 @@ Atlantis supports running custom commands in place of the default Atlantis
 commands. We can use this functionality to enable
 [Terragrunt](https://github.com/gruntwork-io/terragrunt).
 
+You can either use your repo's `atlantis.yaml` file or the Atlantis server's `repos.yaml` file.
+
 Given a directory structure:
 ```
 .
-├── live
-│   ├── prod
-│   │   └── terraform.tfvars
-│   └── staging
-│       └── terraform.tfvars
-└── modules
-    └── ...
+└── live
+    ├── prod
+    │   └── terragrunt.hcl
+    └── staging
+        └── terragrunt.cl
 ```
 
-You would define a custom workflow:
+If using the server `repos.yaml` file, you would use the following config:
+
 ```yaml
-# repos.yaml or atlantis.yaml
+# repos.yaml
+repos:
+- id: "/.*/"
+  workflow: terragrunt
 workflows:
   terragrunt:
     plan:
       steps:
-      - run: terragrunt plan -no-color -out $PLANFILE
+      - run: terragrunt plan -no-color -out=$PLANFILE
     apply:
       steps:
       - run: terragrunt apply -no-color $PLANFILE
 ```
 
-Which you would then reference in your repo-level `atlantis.yaml`:
+If using the repo's `atlantis.yaml` file you would use the following config:
 ```yaml
 version: 3
 projects:
@@ -169,8 +173,19 @@ projects:
   workflow: terragrunt
 - dir: live/prod
   workflow: terragrunt
+workflows:
+  terragrunt:
+    plan:
+      steps:
+      - run: terragrunt plan -no-color -out $PLANFILE
+    apply:
+      steps:
+      - run: terragrunt apply -no-color $PLANFILE
 ```
 
+**NOTE:** If using the repo's `atlantis.yaml` file, you will need to specify each directory that is a Terragrunt project.
+
+
 ::: warning
 Atlantis will need to have the `terragrunt` binary in its PATH.
 If you're using Docker you can build your own image, see [Customization](/docs/deployment.html#customization).
diff --git a/server/events/project_finder.go b/server/events/project_finder.go
index 330f2555cb..f14cb17183 100644
--- a/server/events/project_finder.go
+++ b/server/events/project_finder.go
@@ -51,7 +51,7 @@ func (p *DefaultProjectFinder) DetermineProjects(log *logging.SimpleLogger, modi
 	if len(modifiedTerraformFiles) == 0 {
 		return projects
 	}
-	log.Info("filtered modified files to %d .tf files: %v",
+	log.Info("filtered modified files to %d .tf or terragrunt.hcl files: %v",
 		len(modifiedTerraformFiles), modifiedTerraformFiles)
 
 	var dirs []string
@@ -123,7 +123,7 @@ func (p *DefaultProjectFinder) filterToTerraform(files []string) []string {
 	for _, fileName := range files {
 		// Filter out tfstate files since they usually checked in by accident
 		// and regardless, they don't affect a plan.
-		if !p.isStatefile(fileName) && strings.Contains(fileName, ".tf") {
+		if !p.isStatefile(fileName) && (strings.Contains(fileName, ".tf") || filepath.Base(fileName) == "terragrunt.hcl") {
 			filtered = append(filtered, fileName)
 		}
 	}
diff --git a/server/events/project_finder_test.go b/server/events/project_finder_test.go
index 53ff138da2..5a0d0304d0 100644
--- a/server/events/project_finder_test.go
+++ b/server/events/project_finder_test.go
@@ -189,6 +189,18 @@ func TestDetermineProjects(t *testing.T) {
 			[]string{},
 			"",
 		},
+		{
+			"Should not ignore terragrunt.hcl files",
+			[]string{"terragrunt.hcl"},
+			[]string{"."},
+			nestedModules2,
+		},
+		{
+			"Should find terragrunt.hcl file inside a nested directory",
+			[]string{"project1/terragrunt.hcl"},
+			[]string{"project1"},
+			nestedModules1,
+		},
 	}
 	for _, c := range cases {
 		t.Run(c.description, func(t *testing.T) {