diff --git a/vpc-transit-gateway-association/README.md b/vpc-transit-gateway-association/README.md
index 826807f..b244ecf 100644
--- a/vpc-transit-gateway-association/README.md
+++ b/vpc-transit-gateway-association/README.md
@@ -34,20 +34,21 @@ module "vpc_tgw" {
 
 | Name | Source | Version |
 |------|--------|---------|
-| <a name="module_routing_attachment"></a> [routing\_attachment](#module\_routing\_attachment) | git@github.e.it.census.gov:terraform-modules/aws-vpc-setup.git//routing | tf-upgrade |
+| <a name="module_routing_attachment_ipv4"></a> [routing\_attachment\_ipv4](#module\_routing\_attachment\_ipv4) | git@github.e.it.census.gov:terraform-modules/aws-vpc-setup.git//routing | tf-upgrade |
 
 ## Resources
 
 | Name | Type |
 |------|------|
-| [aws_route.gateway](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/route) | resource |
+| [aws_route.gateway_ipv4](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/route) | resource |
 | [aws_arn.current](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/arn) | data source |
 | [aws_arn.network_account](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/arn) | data source |
 | [aws_availability_zone.zone](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/availability_zone) | data source |
 | [aws_availability_zones.zones](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/availability_zones) | data source |
 | [aws_caller_identity.current](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/caller_identity) | data source |
 | [aws_caller_identity.network_account](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/caller_identity) | data source |
-| [aws_ec2_managed_prefix_list.tgw](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ec2_managed_prefix_list) | data source |
+| [aws_ec2_managed_prefix_list.tgw_ipv4](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ec2_managed_prefix_list) | data source |
+| [aws_ec2_managed_prefix_lists.tgw_ipv4](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ec2_managed_prefix_lists) | data source |
 | [aws_ec2_transit_gateway.gateway_peer](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ec2_transit_gateway) | data source |
 | [aws_ec2_transit_gateway.gateway_self](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ec2_transit_gateway) | data source |
 | [aws_ec2_transit_gateway_route_table.route_tables_peer](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ec2_transit_gateway_route_table) | data source |
@@ -68,7 +69,7 @@ module "vpc_tgw" {
 | <a name="input_network_account_profile"></a> [network\_account\_profile](#input\_network\_account\_profile) | AWS profile of the source account sharing the VPC resources | `string` | n/a | yes |
 | <a name="input_override_prefixes"></a> [override\_prefixes](#input\_override\_prefixes) | Override built-in prefixes by component. This should be used primarily for common infrastructure things | `map(string)` | `{}` | no |
 | <a name="input_private_subnets_ids"></a> [private\_subnets\_ids](#input\_private\_subnets\_ids) | List of private subnet objects including: subnet, label, availability\_zone, id | <pre>list(object({<br>    subnet            = string<br>    label             = string<br>    availability_zone = string<br>    id                = string<br>  }))</pre> | `[]` | no |
-| <a name="input_route_prefix_list_name"></a> [route\_prefix\_list\_name](#input\_route\_prefix\_list\_name) | Shared prefix list name used for routing to TGW.  It is comprised of all of the network CIDR blocks in AWS using TGW. | `string` | `"transit-gateway.prod.ipv4"` | no |
+| <a name="input_route_prefix_list_name"></a> [route\_prefix\_list\_name](#input\_route\_prefix\_list\_name) | Shared prefix list name used for routing to TGW.  It is comprised of all of the network CIDR blocks in AWS using TGW. | `string` | `"transit-gateway.prod"` | no |
 | <a name="input_route_table_label"></a> [route\_table\_label](#input\_route\_table\_label) | Route table lable for the attachment subnets | `string` | `"attachment"` | no |
 | <a name="input_tags"></a> [tags](#input\_tags) | AWS Tags to apply to appropriate resources (S3, KMS).  Do not include safeguard tags here, use the data\_safeguard field for such things. | `map(string)` | `{}` | no |
 | <a name="input_transit_gateway_environment"></a> [transit\_gateway\_environment](#input\_transit\_gateway\_environment) | Transit Gateway Environment (aka, VRF) to which to connnect this VPC | `string` | n/a | yes |
diff --git a/vpc-transit-gateway-association/routing.tf b/vpc-transit-gateway-association/routing.tf
index 9f8f8d7..88c21b5 100644
--- a/vpc-transit-gateway-association/routing.tf
+++ b/vpc-transit-gateway-association/routing.tf
@@ -1,4 +1,4 @@
-module "routing_attachment" {
+module "routing_attachment_ipv4" {
   source = "git@github.e.it.census.gov:terraform-modules/aws-vpc-setup.git//routing?ref=tf-upgrade"
   vpc_id = var.vpc_id
 
@@ -23,19 +23,24 @@ module "routing_attachment" {
   )
 }
 
-data "aws_ec2_managed_prefix_list" "tgw" {
+data "aws_ec2_managed_prefix_lists" "tgw_ipv4" {
   filter {
     name   = "prefix-list-name"
-    values = [var.route_prefix_list_name]
+    values = [var.route_prefix_list_name, format("%v.ipv4", var.route_prefix_list_name)]
   }
 }
 
-resource "aws_route" "gateway" {
-  for_each = module.routing.private_route_table_ids
+data "aws_ec2_managed_prefix_list" "tgw_ipv4" {
+  for_each = data.aws_ec2_managed_prefix_lists.tgw_ipv4.ids
+  id       = each.key
+}
+
+resource "aws_route" "gateway_ipv4" {
+  for_each = module.routing_ipv4.private_route_table_ids
 
   route_table_id = each.value
   #  destination_cidr_block = "10.128.0.0/16"
-  destination_prefix_list_id = data.aws_ec2_managed_prefix_list.tgw.id
+  destination_prefix_list_id = one([for k, v in data.aws_ec2_managed_prefix_list.tgw_ipv4 : k if v.address_family == "IPv4"])
   transit_gateway_id         = data.aws_ec2_transit_gateway.gateway_east.id
 
   depends_on = [aws_ec2_transit_gateway_vpc_attachment.vpc_attachment]
diff --git a/vpc-transit-gateway-association/variables.tf b/vpc-transit-gateway-association/variables.tf
index f09d671..a67a7e1 100644
--- a/vpc-transit-gateway-association/variables.tf
+++ b/vpc-transit-gateway-association/variables.tf
@@ -27,5 +27,5 @@ variable "route_table_label" {
 variable "route_prefix_list_name" {
   description = "Shared prefix list name used for routing to TGW.  It is comprised of all of the network CIDR blocks in AWS using TGW."
   type        = string
-  default     = "transit-gateway.prod.ipv4"
+  default     = "transit-gateway.prod"
 }